Picking up the 6.44-inch Sony Xperia Z Ultra, I don't know whether to laugh or cry. I'm convinced that no mere mortal could wield this beast as their actual phone. At the same time, it's hard not to get sucked in by the superb 1080p display, blazing fast performance, and elegant design. Sony's only offering this phone in an unlocked version for a lofty $679.99 (list), though, so its appeal instantly becomes limited. Is bigger better? Is the biggest the best? With the Z Ultra, Sony aims to find out.

If you're in the market for a big unlocked phone, you're probably better off with the $350 Google Nexus 5($259.00 at Amazon), our current unlocked Editors' Choice, or the Galaxy Note 3, our top pick for phablets. But if you're currently considering the Galaxy Mega or some other monstrous device, then the Z Ultra is the best you can get in the over-6-inch-screen category.

Design, Features, and Display

Without any reference for scale, it would be easy to mistake the Z Ultra for its smaller sibling, the Xperia Z. It's got the same all-glass front and back design, but here the edges are finished in brushed aluminum as opposed to plastic and glass. Despite its massive 7.04-inch height and 3.62-inch width, the Z Ultra is impressively thin at just 0.26 inch, which is thinner than the 0.3-inch iPhone 5s. At 7.48 ounces, it's also not unreasonably heavy, especially given its size. Its gargantuan footprint dwarfs the Samsung Galaxy Note 3, though, and it's nearly half an inch taller than the 6.6-inch tall Galaxy Mega, making it just comically large.

I can comfortably hold the Z Ultra with one hand, but that's about it—my thumb can barely reach about 25 percent of the display while maintaining a secure grip. It also didn't fit into most of my pants pockets without jutting out, which is a deal breaker for me since I don't always have a coat or bag with me. Samsung got Lebron James to make its huge Galaxy Note line look relatively normal, but I'm not sure there's a big enough human that can do the same for the Z Ultra. Still, if you're even considering this phone, you already know that this is strictly a two-handed proposition.

Along the right edge are Power and Volume buttons, a 3.5mm headphone jack, and a flap covering the SIM card tray and microSD card slot. The side-mounted headphone jack makes it even more impractical to keep this thing in pants pockets. On the left side is a flap covering the micro USB port for charging and syncing. Both help keep dust and water out—the Z Ultra meets IP55 and IP58 standards for dust and water resistance, which means you can submerge the phone in up to 1.5 meters (almost 5 feet) of water for up to 30 minutes. The Z Ultra had no problem surviving our dunk test for more than a half hour; just make sure those flaps are securely closed before you subject the phone to any elements.

The 6.44-inch, 1920-by-1080-pixel TFT display is top-notch, boasting a sharp 342 pixels per inch and a wide viewing angle. Sony touts its "Triluminos" technology here, which purportedly delivers a wider color gamut and more vivid images than standard LCDs. I lined the Z Ultra up against the HTC One and the Galaxy Note 3. I found that the Z Ultra's display compared very favorably with the One, showing similarly clean whites, inkier blacks, and largely comparable color reproduction. The Z Ultra has slightly more saturated colors, but doesn't verge into the eye-popping saturation you see on the Note 3's AMOLED display. The Z Ultra's display is the dimmest of the trio, though, with maximum brightness leaving a bit to be desired. Sony also talks up the "X-Reality" feature, which basically bumps up color vibrancy—that feature can be turned off in the settings if you want, but it was pretty hard to tell any real difference either way.

Network and Call Quality

The handset comes unlocked, supporting UMTS (850/900/1700/1900/2100MHz), GSM (850/900/1800/1900MHz), and LTE (Bands I, II, III, IV, V, VII, VIII, and XX). That means here in the states, it'll work on AT&T and T-Mobile with 4G LTE support for both. I popped both carriers' SIMs in and had no trouble connecting to either network. The Z Ultra also supports 802.11a/b/g/n networks on the 2.4 and 5GHz bands, as well as Bluetooth 4.0 and GPS.

I performed call quality tests over T-Mobile in New York City and the results were pretty solid. Voices coming through the earpiece sound full and clear with good maximum volume. Transmissions through the mic sound a bit muffled, but are otherwise natural sounding. Noise cancellation worked well in my tests, as the Z Ultra blocked out a good amount of loud street noise, but I did notice a persistent hiss. This is to say nothing of the absurdity of using such a large device for voice calls, though—this phone will be bigger than most people's faces. In my tests, the Z Ultra lasted for over 24 hours of continuous talk time, a truly herculean effort.

Hardware Performance, Android, and Multimedia

The Z Ultra is powered by a quad-core 2.2GHz Qualcomm Snapdragon 800 processor with 2GB RAM, which is the same processor powering the Nexus 5. Performance is comparable between the two, and the Z Ultra absolutely blazes through anything you throw at it, earning top marks across the board in synthetic tests. Graphically intensive games like Asphalt 8 and Riptide GP2 ran flawlessly and looked absolutely awesome, while complicated Web pages loaded quickly and without issue. Apps launch nearly instantaneously and everything looks pretty amazing on that giant display. It really feels like a slightly smaller and slightly faster Nexus 7($89.99 at Amazon).

Aesthetically, I'm a big fan of Sony's Android skin, running atop 4.2.2 here on the Z Ultra. It's got the same refined feel as the physical design, with useful additions that aren't overdone. The notification shade has a strip of customizable quick settings shortcuts, while swiping to the right on the app drawer gives you options for organizing your apps or deleting them directly from the app drawer. At the bottom of the recent apps list is a strip of shortcuts for Sony's floating apps, but the implementation here has been stripped down a bit. You get basic utilities like a small notepad or calculator that you can move around and resize at will, but its email and browser apps aren't all that useful. Instead of being able to read emails directly in the floating window or navigate to Web pages in the window, you simply get shortcuts that launch the Gmail or Chrome browsers. Multitasking is something that Samsung nails on the Note 3, which really takes advantage of the massive screen real estate—Sony should follow suit to really unleash the power of the Z Ultra.

Our 16GB Z Ultra came with 11.79GB of free internal storage, and a 64GB SanDisk microSD card worked fine for expanding storage. Media support is pretty solid, as the Z Ultra played all of our audio test files except WMA. For video, the Z Ultra played all of our video formats, including DivX and Xvid files at up to 1080p resolution.

The 8-megapixel rear-facing camera can't keep up with cameras found on the iPhone 5s or Samsung Galaxy S4. It takes average shots with decent detail in good light, but struggles in low light with its lack of an LED flash. Granted, LED flashes on smartphones are generally pretty harsh, but the alternative here is blurry or overly grainy shots. Video tops out at 1080p and framerates hovered around 30 frames per second, though it dropped frames in lower light leading to some choppiness in footage.

Conclusions

The Sony Xperia Z Ultra is an absolute monster of a phone, but it's also an elegantly designed, blazing fast monster of a phone. I'm torn here because I'm convinced that no one in their right mind would want to use this as their everyday phone. But it's also so well-built and powerful, and that big screen is so nice for media consumption and gaming, that it really ends up feeling like one of the better small-screen tablets I've ever used. If you want a top-performing, always-connected tablet, though, you can get the Nexus 7 with an LTE radio for nearly half the price.

I get that some people can't get enough of their giant phones, but while phablets like the Galaxy Note 3 are inconveniently big, the Z Ultra is impractically big. And where the Note line adds new and worthwhile features that actually justify the added screen real estate, the Z Ultra is nothing more than a really nice phone with a really big screen. I'm not sure if it's appropriate to compare the Z Ultra with the Note 3, however, and it almost seems like we need a new category for these monstrous devices. The Galaxy Mega and HTC One Max are really the only other Android devices in the Z Ultra's class, and while we haven't tested the One Max yet, the Z Ultra handily beats the Galaxy Mega in every regard. Those who are partial to Windows Phone should consider the Nokia Lumia 1520, which has one of the best cameras we've seen in a smartphone. If you're hell bent on having the biggest, baddest, best-built Android phone in the land, the Z Ultra fills the bill. But if you just want the best affordable unlocked phone, go for the the Nexus 5.

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