The Good: The first phone with Google's Tango software reveals the useful and entertaining possibilities of building AR into a phone. The Bad: Unfortunately, the Phab 2 Pro is a bulky, heavy, mediocre handset with disappointing hardware, an old version of Android and no NFC. The Bottom Line: The Lenovo Phab 2 Pro is a cool toy for developers to unlock the potential of augmented reality but it's not worth buying as a phone. The Lenovo Phab 2 Pro is a phone that should make you sit up and take notice, but maybe not for reasons you expect. It's the first handset with Google's Tango augmented-reality (AR) software, which can add cool virtual objects and realities to the world you see on the phone screen. Think of it as a more accurate, grown-up version of Pokemon Go. The Phab 2 Pro does this by measuring and tracking the space around you. But (and it's a big one), the dozen or so available apps are buggy, inconsistent or just plain bad, and the phone hardware itself fails to stand on its own.If you're really into building AR apps and testing them, the Phab 2 Pro is your only real-world tool -- at least until the Asus Zenfone AR hits store shelves (scheduled for sometime the second quarter of 2017). Previously leaked by Qualcomm, the ZenFone AR will support Google's Daydream View VR headset and apps, and feature a revamped tri-camera system that can achieve depth sensing 3D scanning and augmented reality through Google Tango. If nothing else, the Zenfone AR demonstrates that AR can be delivered in a slim, lightweight package. Still, we don't know whether it will improve the issues we experienced with Tango's limited content and inconsistent quality.And even if it sounds unbearable to wait until the ZenFone AR makes its debut, I nevertheless recommend you avoid the Phab 2 Pro. It truly feels like a work in progress -- not a full-fledged system for either the hardware or the software. And, because it fails to live up to its single purpose, AR, it's not something you should even consider buying.Here's what's good: The 6.4-inch screen makes everything easy to seeThere's a high-capacity 4,000mAh battery and a fingerprint reader The phone's $500 price keeps it relatively affordable (it converts to about \u00a3400 or AU$670)You get a sense for how AR can enhance your life (more below)Here's what's bad: The phone's huge and heavy -- I have small hands and couldn't comfortably typeIt runs Android 6.0.1 Marshmallow, not the current 7.0 NougatPhotos can be grainy and dull, and take 5 seconds to process fully, even in abundant lightingI often smudged the camera when trying to use the rear fingerprint reader to unlock the phoneThere's no NFC, which also means no Android PayCall quality was sometimes awful (the other end couldn't hear me), and once, it took three attempts to eject the SIM card tray. The aluminum body and glass screen sustained fine scratchesThe battery dies a quick death when you use ARAR apps are sometimes confusing and can be buggy. For example, graphics on some games are terribly low-fi and some are prone to freezing. Apps that measure and track the room, like Lowe's Vision, don't always work accurately or easily to measure and place virtual items.Apps superimpose items like virtual pets, dinosaurs and dominoes over the real-world surroundings you see through your screen, but don't interact with them convincingly. Dominoes hang off a table's edge instead of falling to the ground. Virtual dogs and cats run through their loops without being aware of people or objects that exist in the scene.Battery life and speed statsThe Phab 2 Pro may have a humongous battery, but you'll get less life out of it than you'd think. Part of that is because complex AR software sucks up a lot of power, and that's completely understandable. Even without background software running, Lenovo's phone only logged 11 hours of battery life on our continuous video loop test. That's just about average, but you'd expect more raw power from a phone with such a big honking battery.In fact, the phone's speed lagged severely behind high-end phones like the Google Pixel XL and iPhone 7 Plus, in both benchmark testing apps (we use Speedtest.net, Geekbench 4 and 3DMark) and day-to-day usage. The speed is fast enough that most of the time you probably wouldn't know the difference -- unless you're trying to take back-to-back shots with the camera.It might still make you an AR believerEven though you shouldn't buy the Phab 2 Pro, the large-screen phone does unlock the terrific possibilities of augmented reality and why you might want to experience it. And believe me, it's coming. Apple is already rumored to be including some AR elements in next year's 10th anniversary iPhone.