Friday, March 11, 2016

Fitbit Blaze review: looks only

When Fitbit introduced its Blaze smartwatch back at CES, many people hyped it up as an Apple Watch competitor. It's $150 cheaper, but still features a color touchscreen, notifications, a host of fitness-tracking features and impressive five-day battery life. It's also the most stylish Fitbit yet, with interchangeable watch bands that include leather and metal options.

But in the week I spent testing the Blaze, I realized it's not a smartwatch in the conventional sense of the word. The Blaze is a fitness-first device that does most of the same things as Fitbit's Surge fitness band, just in a more stylish package. It looks and acts like a smartwatch, but if you expect it to have as many features as the Apple Watch or most Android Wear devices, you'll be disappointed. But does the Blaze at least bring enough to the table to succeed on its own merits?

Pros
  • Interchangeable bands
  • Good fitness-tracking features
  • Excellent battery life

Cons
  • Feels cheap
  • Limited feature set compared to other smartwatches
  • It's kind of ugly

Summary

The Blaze continues Fitbit's tradition of making quality fitness trackers, but the device is ultimately let down by an uninspired design and a cheap-feeling design. Those deficiencies in style and materials make for a wearable you won't actually want to wear all day, which makes it a tough sell.

Hardware

The Blaze is made up of two parts. The first is a band connected to a stainless steel frame. All the guts of the Blaze itself are contained in a small, standalone black rectangle that features a color touchscreen on the front, heart-rate monitors on the back, and three buttons on the sides. Just snap the little tracker into the frame, and then you're good to go.
The $200 base model comes with an elastomer sport strap, available in black, blue or plum. If you want to use a different band, you don't swap the band itself; you just pop the tracker out and insert it into a new frame-and-band combo. I tested the black leather strap, which sells separately for $99 and comes with another steel frame. While it's simple enough to remove the bands, Fitbit clearly thinks that popping out the tracker and dropping it into a new frame makes for a better experience.
Even if you don't own multiple bands, you'll be popping the tracker in and out of its frame to charge it. The tracker drops into a weird little plastic charging frame for power; you can't rejuice it without removing it from the strap. It's odd and rather awkward, but fortunately you won't need to charge it very often. Fitbit promises five-day battery life, which is about how long my review unit lasted. If you're doing lengthy workouts every day, you'll probably burn through the battery faster, but even so, I did three in a five-day period and the battery held up just fine.
As for actually wearing the Blaze, it's a lot more comfortable than I expected. Perhaps my nerves were shot when I first tried the device at CES, but I was initially unimpressed with it. Though the watch lacks the polish of a premium product, I didn't mind wearing it for extended periods of time. The Blaze is very light, which helps it recede into the background while you're wearing it. The elastomer strap is clearly the better choice for working out, but the rest of the time I preferred the leather option. Fitbit's silicone is good enough, but it's definitely not as comfortable as Apple's own sport bands.
The leather option felt more comfortable to wear for extended periods, but neither band feels particularly well crafted. With the base $200 edition and elastomer strap you're getting what you pay for, but at $100 the leather strap isn't exactly cheap. For the money, I would have expected a higher-quality, more supple feel. That said, over the week or so I wore it, I did manage to break the strap in a bit, and it ultimately became my go-to band when I wasn't exercising.
Ultimately, the whole package feels decent for the price, but it's not something I looked forward to wearing every day. It's just not fashionable, and it feels rather cheap. It lacks the retro futurism of the Moto 360 and the craftsmanship of the Apple Watch. Yes, it's less expensive than either of those devices, but for a wearable to be successful, people should actually want to wear it every day, and that just wasn't the case for me. I'd even be more inclined to wear Fitbit's new Alta tracker over the Blaze: It makes no bones about being just a fitness tracker, whereas the Blaze is is in the awkward position of being a gadget that tries but fails to be stylish. It's hard to make a smartwatch that doesn't look like a tiny computer on your wrist, but the Blaze is even less successful in that regard than its rivals.

Software

Most Fitbit devices have a bare-bones UI, the better to accommodate their tiny displays. That's not the case with the Blaze, which features a larger 1.25-inch color touchscreen with a 240x180 resolution. As such, there's a lot more you can do directly on the device compared to older Fitbits.
The "home" screen here is a watch face; there are four to choose from in the Fitbit app. The default analog watchface crams in a surprising amount of info: besides viewing the time, you can tap the screen to cycle through the steps and distance you've taken that day as well as view your heart rate, calories burned, stairs climbed and the date. By default, a ring around the clock dial also shows you how close you are to getting in your recommended 10,000 steps per day.
I liked the concept of this face, but ultimately it was a little hard to actually read as a watch, so I used another option called "Pop" that shows the time in bold numbers alongside little icons indicating how close I was to meeting my daily goals. Tapping the screen let me cycle through steps, heart rate and calories burned.
From the watch face, you can swipe to the right to access the Blaze's other main "apps" (for lack of a better word): Today, Exercise, FitStar, Timer, Alarms and Settings. The last three are self-explanatory; we'll delve more into those first three now. While you can view all sorts of fitness data from the watch face, you're better off jumping into the "Today" view, which presents an easy-to-read summary of your progress, including steps, total distance, flights of stairs climbed, heart rate and calorie burn. All of this data is available in the Fitbit smartphone app, but it's convenient to view it right on the watch itself. That said, it's strange that the "active minutes" measurement, which measures "moderate" activity done in periods of 10 minutes or more, isn't available on the watch.
If you want to formally track a workout, the exercise app is where you do it. There you'll find options to record outdoor running, biking, treadmill, elliptical and weights, with a generic "workout" catch-all for everything else. It covers the basic set of activities that Fitbit expects users will want to track and that the Blaze can capture with some degree of accuracy, and it's similar to the feature set you'll find on competing products. People who are really serious about tracking their workouts will probably prefer more expensive and purpose-built tracking devices, like a triathlon watch or cycling computer, but for the Blaze's target audience, these preset workouts should be enough.
Most of my exercise comes in the form of running, but the Blaze includes a feature called FitStar that includes three different short cardio routines: an eight-minute warmup sequence, a seven-minute workout that puts you through 13 different exercises (pushups, jumping jacks, crunches, squats, etc.) and a 10-minute ab workout. It's a smart addition, and hopefully over time Fitbit will add even more programs. Fitbit did confirm the Blaze would get software updates over time, the first of which will add reminders to get up and move around.
That's it for native apps, but there are a few other software features worth noting. From the watch face, you can swipe down to control music playback on your phone with basic pause / forward / back controls. Additionally, you can turn the volume up and down using the two buttons on the Blaze's right edge. The watch also supports a limited set of notifications: You can see incoming calls, with the option to answer or dismiss them; view incoming text messages; and receive alerts from your calendar app. (If you're on iOS, it has to be the default Calendar application.)
While I occasionally longed for the Apple Watch's various reminders and apps, there's something to be said for paring down. Besides, I've already turned off most notifications on my Apple Watch anyway. Rather than offer its users that option, Fitbit just decided to limit the notifications out of the box. It's a logical approach, as Fitbit hasn't positioned the Blaze as a true smartwatch competitor. The Blaze's non-fitness features are limited, and that's probably a good thing: The device has a small screen, and trying to do more with it would probably make for a frustrating experience.

In use

What really matters for a device like this is what it's like to wear day to day. Even though the Blaze's design didn't bowl me over, it continues Fitbit's long tradition of offering solid activity tracking features that work well on their own, in the background. On days when I wasn't doing a full workout, the Blaze largely left me alone. I'd get the occasional notification for text messages, and I of course checked the time and my step count, but that was it.
All told, the Blaze demands less attention than the Apple Watch, and there's definitely something to be said for having a smartwatch that isn't constantly begging to be used. That's a good thing, because the screen on the Blaze is rather small and unresponsive. I'm not sure if that's a hardware or software issue, but my taps to the screen didn't always register. The "raise your wrist to see the time" gesture was similarly hit-and-miss; I wish it were more sensitive by default.
The Blaze becomes more useful when you work out on a regular basis. When I started an outdoor run, the Blaze hooked up to my phone to track and save my route, just as Runkeeper does. As you run, you can see the total distance, steps taken, current and average pace, and calories burned. As for the accuracy of its distance tracking, the GPS connection with my phone means it gave me near-identical results to what both Runkeeper and the Apple Watch reported.
Still, there were some differences in the data the Apple Watch and Blaze reported. Though the Blaze typically showed a higher step count than the Apple Watch, it said I didn't travel as far. Similarly, when running on the treadmill, the Blaze reported significantly different number versus the Apple Watch -- but it seemed to be more accurate, at least when compared to what the treadmill itself said I was doing. The Apple Watch typically says I run a lot faster than the treadmill (a nice ego boost) but the Blaze's readout was closer to the treadmill's, even though it says I'm slower. What's most important is a tracker being consistent, and the Blaze is.
While the Blaze's exercise tracking features work well enough, there was one feature I missed from other apps like Runkeeper or the Apple Watch's built-in fitness app: I found it strange that you couldn't set goals for a particular workout -- say, run for 30 minutes or burn 300 calories. It's nice to get a sense of how far along you are in the middle of a workout, and while you can set a goal in your head, it makes it a little harder to see how close you are towards meeting it. Getting specific feedback from the watch during my workouts would have been helpful.
That said, if you're the type of person who sometimes forgets to formally track a workout, the Blaze has you covered. The tracker can automatically recognize various activities and add them to your workout history. By default, it'll only add an activity when you keep it up for 15 minutes or more, but you can adjust that in the settings for when you do shorter workouts. In my tests, it worked like a charm.
While the Blaze didn't recognize my four-minute warmup walk on the treadmill, once I started running, my heart rate went up and the Blaze proceeded to track my entire run. It was even smart enough not to terminate the workout when I took a short walking break. The downside is that using the auto workout feature doesn't track distance or use the GPS to record a route, so you don't get as much data as you would otherwise.

The competition

The Blaze has a lot of competition, both inside and outside of Fitbit. The closest thing that Fitbit offers is the Surge, which has a nearly identical feature set. The Surge, which costs $50 more, offers built-in GPS for phone-free run tracking, while the Blaze instead brings a more watch-like design, interchangeable bands and those FitStar exercise routines. The $130 Fitbit Alta and $150 Fitbit Charge HR both also have displays (albeit tiny ones), but lack some key features the Blaze offers: The Alta doesn't have heart rate tracking or music controls, for instance, while the Charge HR doesn't support music controls or incoming notifications.
Comparable products from other brands include the Basis Peak ($150),Microsoft Band 2 ($175), Garmin Vivosmart HR ($150) and Polar A360($200), to name just a few. All of these devices have screens of some sort, and all will show you some subset of your phone's notifications. With the exception of the Polar A360, all are cheaper than the Fitbit Blaze, but again, the features vary, so choose carefully.
Of course, the Apple Watch ($350-plus) and Android Wear devices like theMoto 360 Sport ($300) deserve mention as well. Fitness tracking is actually one of the best things about the Apple Watch, and it does a heck of a lot more than the Blaze. The Moto 360 Sport doesn't stack up as well against the Fitbit as an exercise tracker -- but again, Android Wear makes for a more versatile device overall.

Wrap-up

If you think of the Fitbit Blaze not as a smartwatch, but just the latest in a long line of fitness trackers, the device is fairly successful. It's $50 cheaper than the Surge but has nearly the same feature set. It also adds some important features like a color display, changeable bands, and the most stylish design we've ever seen on a Fitbit product. It's definitely not as attractive as competing smartwatches, but it at least doesn't scream "fitness tracker" like the rest of Fitbit's lineup.
The company also gave the Blaze a purposefully limited feature set, rather than trying to make a true Moto 360 or Apple Watch competitor. That might come as a disappointment to those who thought the Blaze would scratch the smartwatch itch at an affordable price, but if you're looking for a fitness tracker with a smartwatch-inspired design and a few nice extras, the Blaze is worth considering. It combines robust fitness tracking, excellent battery life and a few other tricks in a package that's more attractive than anything else Fitbit has ever put out.
The big knock I have against the Blaze is that it still feels far more gadgety than I'd like for a device you prominently display on your wrist. Obviously, looks are subjective and some might fall in love with the Blaze's design. But it faces stiff competition from the likes of the Apple Watch and Moto 360. The Blaze works best if you wear it on your wrist every day, forsaking all other watches, smart or otherwise. Ultimately, that's not a commitment I'm willing to make.

HP's 15-inch Spectre x360: Come for the screen, stay for the battery life


Spectre x360 15t (2016)ore

Before there was a Surface Book, there was the Spectre x360. Though the laptop is sold by HP and has HP's name on it, it was designed in close collaboration with Microsoft, which had input on everything from the touchpad to the WiFi radio. The result was a beautiful, well-performing machine with one clean Windows build -- and it gave us an early glimpse at what Microsoft could accomplish when it set about designing a laptop. The 13-inch x360 was one of our favorite laptops of 2015, and now HP is back with a larger model. The 15-inch version ($1,150 and up) promises to be everything its little brother was, complete with a 360-degree touchscreen and the same unibody aluminum design. Except, you know, it offers more screen real estate, along with a higher-res 4K option. And with it weighing in at four pounds, you'll be hard-pressed to find something this size that's this thin and light.

Gallery: HP Spectre x360 review (15-inch, 2016) | 37 Photos


Pros

  • Thin and light for a laptop this size
  • 4K screen option on this 15-inch model
  • Well-constructed
  • Comfortable keyboard
  • 10-plus hours of battery life
  • Almost no bloatware
  • Good sound quality
 

Cons

  • Touchpad can be a bit flaky
  • No performance gains over the smaller version; discrete graphics not an option

Summary

The Spectre x360 15t is a bigger version of the original x360 we reviewed last year. It brings the same well-constructed design as its smaller stablemate, along with a comfortable keyboard and a nearly bloatware-free Windows install. Because it's so thin and light for its size, it's a good pick for people who want more screen real estate (not to mention a 4K resolution option). It's a fine, well-rounded machine; just don't expect any performance gains over the smaller model. If you do indeed need some processing muscle to match those extra pixels, you'll need to look elsewhere.

Hardware

True to its name, the 15-inch Spectre x360 is a bigger version of the 13-inch model that we tested last year. Like the smaller edition, it has a beautiful machined aluminum body with rounded corners, blunt edges and a 360-degree lie-flat hinge that makes the machine look equally thin regardless of whether it's in clamshell or tablet mode. The keys are also made of metal and are as well spaced as you'd expect on a machine with this large a footprint. Though the buttons look shallow for a laptop this size, in practice they're comfortable to type on, not to mention quiet. To match, there's an extra-wide, single-button trackpad that gave me ample space to move around but could be a little flaky, even with single-finger tracking. Hopefully HP can fix that through a firmware update.
What you might not expect, though, is how light the thing is. Typically I dread reviewing 15-inch machines because I know they'll weigh down my bag and take up a lot of space on my desk. I can't do much about the larger footprint in this case, but at 4.05 pounds, it's definitely easier to tote around than other 15-inch systems. The x360 is also thinner than I would have guessed, at 0.63 inches thick. That won't save me space on my desk, but it at least makes it that much easier to hold the machine in hand.
Though the 15-inch model has a bigger footprint, it barely offers more ports along its edges. Like its smaller stablemate, it includes three USB 3.0 connections, a Mini DisplayPort, an HDMI socket, an SD card reader, a headphone jack and a volume rocker, for use in tablet mode. The only other thing you'll get here is a smaller USB Type-C port -- an important addition, considering how ubiquitous the standard is getting. In fact, I wouldn't be surprised if HP added it on the 13-inch edition too.

Display and sound

One of the main things separating the 15-inch Spectre x360 from the 13-inch version is its optional 3,840 x 2,160 display. Unfortunately, the unit I tested had a lower-res 1,920 x 1,080 panel, so we're going to have to trust that the 4K display is as sharp and pixel-dense as the 4K displays on every other 15-inch laptop. (I believe it is.) The real shame there is that I would have liked to know how the battery fares when forced to light up those extra pixels, though I can at least attest to the machine having good runtime at 1080p (more on that later).
Even with that lower resolution, I still enjoyed looking at the display. Setting aside the fact that 1080p is actually gentle on my not-so-good eyes, the colors are pleasant and the IPS panel allowed for wide enough viewing angles that I could spend hours working next to a window on a sunny day. Is it the sharpest, most color-accurate laptop screen money can buy? Hardly. But your eyestrain will be kept to a minimum, and, if you're like me, you'll enjoy the extra screen real estate when you're working in a spreadsheet or jumping among a dozen browser tabs.
Apple's acquisition of Beats meant HP had to team up with a new audio company to power its speakers. It landed on Bang & Olufsen, which previously provided its know-how to other PC makers like ASUS. I'd say that although HP didn't necessarily plan on parting ways with Beats, it definitely traded up. The sound coming out of the grilles on either side of the keyboard is balanced and not too bass heavy.

Performance and battery life

PCMARK 7PCMARK 8 (CREATIVE ACCELERATED)3DMARK 113DMARK (SKY DIVER)ATTO (TOP READS/WRITES)
HP Spectre x360, 15-inch (2.4GHz Core i5-6200U, Intel HD 520)5,0403,458E2,672 / P1,526 / X4203,542561 MB/s / 284 MB/s
Razer Blade Stealth(2.5GHz Intel Core i7-6500U, Intel HD 520)5,1313,445E2,788 / P1,599 / X4263,4421.5 GB/s / 307 MB/s
Toshiba Radius 12(2.5GHz Intel Core i7-6500U, Intel HD 520)5,4583,684E2,865 / P1,6223,605552 MB/s / 489 MB/s
HP Spectre x2 (1.2GHz Core M7-6Y75, Intel HD 515)3,3953,307
E1,884 / P1,148 / X331
2,737554 MB/s / 281 MB/s
Microsoft Surface Pro 4 (2.4GHz Core i5-6300U, Intel HD 520)5,4033,602
E2,697/ P1,556/ X422
3,6141.6 GB/s / 529 MB/s
Lenovo Yoga 900(2.5GHz Core i7-6500U, Intel HD 520)5,3683,448
E2,707 / P1,581
3,161556 MB/s / 511 MB/s
Microsoft Surface Book(2.4GHz Core i5-6300U, Intel HD 520)5,4123,610
E2,758 / P1,578 / X429
3,6231.6 GB/s / 571 MB/s
Microsoft Surface Book(2.6GHz Core i7-6600U, 1GB NVIDIA GeForce graphics)5,7403,850
E4,122 / P2,696
6,1911.55 GB/s / 608 MB/s
For the purposes of this review, I tested the entry-level $1,150 model, which has a dual-core 2.4GHz Intel Core i5-6200U processor, 8GB of RAM, integrated Intel 520 graphics and a 256GB solid-state drive. You'll find similar specs in many smaller PCs, including Microsoft's Surface Pro 4 and some lower-end Surface Book configurations, among others. And it performs about the same too, both in benchmarks and in real-world use. Unlike competing notebooks, though, the x360 comes with a near-blank Windows 10 install, with little bloatware in sight. Just shortcuts to Netflix, Snapfish and a handful of HP-made programs, like HP ePrint. Not bad at all.
In my time with the x360, I treated it as a work-and-play machine, which means I was typically juggling nine pinned tabs in Chrome (plus lots of open ones), Slack, Spotify and intermittent file downloads. The machine boots into the desktop in 11 seconds, which is on par with other modern laptops. The Lite-On-made SSD can read data with the best of them too, notching average max speeds of 561 megabytes per second. That said, you'd absolutely get faster writes if this were a PCIe-based drive, specifically.
Aside from sheer processing power, I was impressed by the Intel-made 2x2 802.11ac wireless radio. I enjoyed a reliable connection even on what should have been slow, spotty networks. During jury duty, for instance, I had no problems on the public WiFi network that hundreds of other people were using -- and that people around me were complaining about. I managed to get online anyway.
Throughout, the laptop stayed cool. I should know: While serving jury duty, I spent my days with the machine on my lap getting work done. I may have lost my patience, but my legs at least avoided any contact burns.
BATTERY LIFE
HP Spectre x360 (15-inch, early 2016)10:17
Surface Book (Core i5, integrated graphics)13:54 / 3:20 (tablet only)
MacBook Air (13-inch, 2013)12:51
HP Spectre x360 (13-inch, 2015)11:34
Surface Book (Core i7, discrete graphics)11:31 / 3:02 (tablet only)
Apple MacBook Pro with Retina display (13-inch, 2015)11:23
iPad Pro10:47
Chromebook Pixel (2015)10:01
Lenovo Yoga 9009:36
Microsoft Surface 39:11
Apple MacBook (2015)7:47
Dell XPS 13 (2015)7:36
Microsoft Surface Pro 47:15
Microsoft Surface Pro 37:08
HP Spectre x26:43
Razer Blade Stealth5:48
Toshiba Radius 125:12
HP says the machine's 64.5Wh battery should run for up to nine and a half hours on a charge. I can't speak for the 4K edition, but the lower-res 1080p model I tested actually beat that estimate, lasting exactly 10 hours and 17 minutes before giving up the ghost. Mind you, that was with an HD video looping, WiFi on and the brightness fixed at 65 percent. With a less taxing workload, you might be able to eke out even more runtime. Even as is, though, 10-plus hours is more than respectable for a modern laptop, though it must be said that the 13-inch version we tested a year ago lasted even longer.
As a bonus, when you do need the charger here, it takes up remarkably little space -- it's just a small, lightweight cube. Anyway, that's not a dealmaker by any means but something to consider if you're worried about the weight and footprint of a 15-inch machine; the space you'd save with a 13-inch laptop might be offset somewhat by its bulkier power brick.

Configuration options and the competition

The 15-inch x360 starts at $1,150 with a 2.3GHz dual-core Core i5-6200U processor, integrated Intel HD 520 graphics, 8GB of RAM, a 256GB solid-state drive and a 1080p display. From there, you can get 16GB of RAM ($80), upgrade to a 4K screen ($60) or double the storage capacity to 256GB ($200). There are other processor options too, including Core i7-6500U ($60) and Core i7-6560U ($200), the latter of which includes beefier Intel Iris graphics. If you care, that in-between Core i7-6500U chip can be configured with either 8GB or 16GB of RAM while the higher-end 6560U processor is 16GB only. All told, assuming you went with all the upgrade options I just ticked off, the price would be $1,690 before tax.
If you're shopping around, the 15-inch Retina MacBook Pro is an obvious competitor here, in that it's also a slim, lightweight 15-inch machine with a high-res screen (2,880 x 1,800 in this case). Incidentally, it's actually thicker and heavier than the x360 (4.49 pounds and 0.71 inches thick), and that's without a 360-degree hinge or touchscreen weighing it down. For that starting price of $1,999, though, you get some admittedly more powerful components, including a quad-core Core i7 processor and Intel Iris graphics, with 16GB of RAM and 256GB of solid-state storage standard. From there, you can add a discrete AMD GPU or a faster CPU, but even on the base model the trade-off is clear: Though it's heavier and more expensive than the x360 and isn't as versatile as a convertible, you get more-robust performance in return. Your call on what's most important.
Back in the world of Windows PCs, there aren't that many laptops that directly compete with the 15-inch Spectre x360, but I can think of at least two that might fit the bill. The first is the Dell XPS 15, which also has a 15-inch, 4K-optional display and starts at a similar 3.9 pounds. (With a tapered design that runs between 0.45 and 0.66 inches thick, it's also thinner at points, too.) Though it starts at $1,000, the specs you get for that price don't compete at all with the Spectre x360 we're looking at today. The base model includes a Core i3 processor, 8GB of RAM, a non-touch 1080p screen and a 500GB hybrid hard drive.
But say you just wanted a touchscreen. The cheapest touch-enabled model on offer starts at $1,999 and also entails a big step up in specs, including a 4K screen, a quad-core Core i7 processor, 16GB of memory and a 2GB NVIDIA GTX 960M GPU. Basically, then, there's no in-between option, where you can get a Core i5 processor, or a touchscreen, with a lower resolution. With the XPS 15, Dell makes up-sells almost unavoidable; the specs you're likely to pick are more in line with a souped-up MacBook Pro. That's not a bad thing, but it's no doubt more money than some of you were planning on spending.
Last, there's Microsoft's Surface Book ($1,499 and up), though that's a less perfect comparison, mostly because it has a smaller 13.5-inch screen, not a 15-inch one. That said, its high-res, 3,000 x 2,000 display and slim, versatile design (it's a detachable tablet) make it a possible contender. As do its specs: Certain high-end configurations have a discrete NVIDIA GPU in the detachable keyboard portion, allowing for likely stronger performance than what the Spectre x360 is currently capable of.
As a warning, some early units were plagued by hardware and software issues, but Microsoft claims to have addressed them through a series of firmware updates. It's likely, then, that early adopters got the shortest end of the stick, but it's worth considering anyway before plunking down all that money.

Wrap-up

The 15-inch Spectre x360 is a bigger, but not necessarily more powerful, version of the original that came out last year. The main benefit is extra screen real estate and, if your budget allows, the optional 4K resolution. Even at its best, though, the 15-inch x360 has similar specs to many 13-inch notebooks; that extra heft doesn't translate to extra processing clout or longer battery life. If all you want is a bigger screen that's easier on the eyes while you're working for long stretches, the 15-inch x360 is well-constructed and compact for its size.
Personally, that's not what I'm looking for in a laptop, but I'm sure there are people out there who are in the market for a bigger-screened thin-and-light. (If it helps, Dell says the XPS 15 is outselling the XPS 13, so I know for sure that that's the case.) If, however, you need some performance muscle to match your higher-res screen, you'll need to pay more for a machine with meatier specs, like the Dell XPS 15 or the MacBook Pro. It all depends on your priorities.