When it comes to smartphones, what drives your choices? If looks and materials are important to you, the bulky, plastic-shielded Asus Zenfone 2 won't make your shortlist. But if all the stuff under the hood counts for more points, then the gigantic, hulking shape of the device won't matter to you as much.

The massive Android phablet takes the "computer in your pocket" trope quite seriously. It's an impressive multitasking machine that's adept at video, web surfing, and running all manner of apps, though it suffers just a bit of a lag with some heavier games. It comes with a choice of two different high-end Intel Atom processors, both quad-core, both 64-bit. One version (costing $199) features a 1.8 GHz CPU with 2GB of RAM, and 16GB of memory. The faster phone (costing $299) has a 2.3 GHz processor with 4GB of RAM, and includes 64GB of internal storage. It's the first Android phone to feature that much memory, the same as the Lumia 640 XL.

The Zenfone 2 does indeed come with top-shelf specs, and it's a shame they're packed in such an unattractive plastic body. To call it alarmingly huge is an understatement. The heavy, thick monolite shell expands rapidly from 3.9 millimeters at the edges to almost 11 millimeters at the center. All that interior volume in necessary to house the gigantic, integrated 3,000mAh battery, which is big enough to assure the phone lasts at least a full day, and often a couple of days, between charges. Switch on the phone's "Ultra-saving Mode" and you can extend your battery life to three days. Impressive.

The power button sits at the top of the device, and the volume buttons can be found on the rear—just beneath the camera, à la LG. Removing (yep) the plastic cover grants access to a microSD slot that accepts cards up to 64GB, as well as two microSIM slots. One microSIM slot works with up to 150Mbps 4G data, while the other is limited to 2G. The compatibility of both slots extends only to GSM Networks, meaning you can use the Zenfone 2 with AT&T and T-Mobile, but not with Verizon, Sprint, or US Cellular.

Give It a Shot

Other than the differing chipsets inside, the two models of Zenfone share very much the same hardware. Both showcase a 5.5-inch HD IPS display made of Gorilla Glass 3 with a remarkable pixel density of 403ppi. The main camera has a 13-megapixel sensor with dual-LED flash light, a bright f/2.0 aperture, HDR, and Manual and Low Light modes. In optimal shooting conditions, it quickly takes usable images with good details. Some levels of noise creep into the more dimly-lit areas of the photos, but you can prevent those by tweaking the settings in the camera's manual settings, which abound. There's also a "Super Resolution Mode" that stitches together four different shots to make a single, 52-megapixel image. Neat, but it fails in achieving a visible improvement in the overall quality of the image.

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When the sun goes down, the camera's Low Light mode increases sensitivity by 400 percent to create incredibly bright night shots. I was able to get shots of scenes where a normal camera couldn't detect anything in the dark. Resolution in this mode is limited to 3 megapixels, and some areas can be blurred, but still: objects you couldn't see actually become visible. The front camera does a neat trick: it can capture up to 140 degrees of your surroundings by combining seven different shots. This feature is appropriately named the "Selfie Panorama." Though I felt no need for this kind of feature, I must admit selfies can make much more sense with a lot of surroundings in the background. Point taken.

There are countless other camera features—so many, in fact, that I found myself just using the same two or three options all the time. Making the abundance of camera tricks seem even more like overkill is the fact that, overall, the camera doesn't outperform the best ones out there, such as the iPhone's top-shelf shooter. If you're looking for a good "camera phone," one that you can carry in place of a dedicated compact camera, there are better options.

The Skin I'm In

Asus has chosen to graft the company's own ZenUI skin atop Android Lollipop. The heavy customization in ZenUI won't appeal to Android purists, but it comes with some interesting features. Parents will like the ability to activate user profiles for guests and kids that can hide certain apps (and eventually notifications) and also to shut down access after a predefined period. I really liked the custom gestures. The ones I most appreciated were the convenient tricks that reminded me of the OnePlus One. The "Motion Gesture" lets you take screenshots simply by shaking the phone twice. "Touch Gesture" activates specific apps from standby with a quick swipe: draw an S to launch the messaging app, C to open the camera, W if you want to open the browser, V for the phone, E for email, and Z for ASUS Boost—that last one kills everything running in the background, clearing up large chunks of RAM in seconds. A double tap on the screen wakes up or suspends the phone instantly—nice, since it eliminates the need to stretch your finger all the way up to that un-handy power button. And much like we've seen on other big phones, double-tapping the home key engages a one-handed mode that shrinks the screen down to a smaller size. You can manually adjust the size of the smaller screen, going down to 3.5-inches.

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Swiping up from the bottom of the display brings up a control panel. It's here the Zenfone 2 offers some deep levels of personalization, with a mixture of fonts, wallpapers, icons, themes, and scroll effects. Altogether, there are hundreds of possible combinations that determine how your phone's UI looks. You can even adjust color temperature, vividness and saturation of the display.

Sadly, the phone comes with an egregious number of redundant apps pre-installed. Minutes after I set up my Zenfone 2, I deleted Jawbone's UP app, Zinio, ZenCircle, and Omlet Chat. The factory-installed apps for the calendar, web browser, messaging, and music can't be uninstalled. If you prefer to use Google's superior apps, they will live side-by-side with Asus's detritus. There's even a "What's Next" feature—a seeming rip-off of Google Now that gives you advance alerts based on your calendar.

Which Way to Zen?

The Asus Zenfone 2 is not a smartphone you fall in love with at first sight. And yet, it's one of the best midrange phones around, with remarkable battery life, a great screen, and powerful processors that can do anything you'd ask of your mobile. Between the two versions, I'd recommend the cheaper one—the low cost and huge battery easily make it one of the most interesting devices in the under-$200 price range.

If you're willing to spend $300 on a phone and you crave the outsider chic that the funky Asus hardware offers, there are better options than the spec'd up, more expensive Zenfone 2 model. Consider instead the OnePlus, the Alcatel Idol 3 or the Sony M4 Aqua.