The design of the rear display, which I consider the most "important" display on this device (since it's what could get you to buy this phone over its competitors), is fairly simple. It is a small 5.1-inch curved AMOLED display located directly under the camera sensors at the top of the "bezel." It has a resolution of 720 x 1520 pixels with an aspect ratio of 19:9, making it a bit taller than the average main display. It also means a measly PPI of 330, yet that's not the worst considering this is just the extra panel. As for viability, this rear display has a maximum brightness of 330 nits, essentially meaning the rear display is useless in direct sunlight. As for the actual display, it is covered in a coating that makes it mimic the rear color of the phone while not in use. Thus, while the screen is off, the always-on display can turn on. and instead of showing white text and icons on a black slab, it will appear as if it's projected onto the colored back of the phone. Pretty cool, huh? This surprisingly didn't affect colors on the display much, although it's not like that would matter -- you aren't supposed to stare at this for tens of minutes at a time or consume media on it. Nubia also included two fingerprint scanners, which is actually pretty smart. On both the left and right sides of the phone, you will find a dual fingerprint and power button. You can unlock and lock with both sides, so you can always use the same finger to unlock the device no matter which display you are using. The Nubia Z20 dual-screen software is actually very limited. There is only one real dual-screen software feature, a constant floating button that lets you swap screens. That's pretty much it. Seriously, that is all you get beyond the aforementioned always-on functionality. Even though they've invested so much on such a unique form factor with great (hardware) execution, it seems like they had not figured out any ways to exploit this back display beyond using it for the rear camera or as a passive always-on display. Why would anyone swap displays and use the back panel over the decidedly and markedly superior front display? After I sent the device back, it actually got a software update that automatically switches between the front and back display just by flipping the phone over. That's a nifty feature (assuming it works well enough to not get on your nerves), but again, is that all that they can offer?

The Nubia Z20 has you go through extra steps to arrive at a worse user experience

To make things worse, the dual-screen experience isn't even that great! At first, it seems like it will be fine and dandy: just flip around the screen when you need to use the back display, for whatever crazy reason. For a good bit of time, this is fine, it feels new and futuristic. But it won't take long for you to realize that there is no real reason to willingly switch to this display. And then, you start trying to use video calling apps or Snapchat, or just want to test the camera with a selfie. This is where it just becomes annoying. Sending a quick pic or snapping a quick selfie goes from a two-second process of opening the app and hitting the shutter to swapping the display, turning the Nubia Z20 around, then opening the app and hitting the shutter. If you are outside when it's even a little sunny, you won't even be able to see the display because it just doesn't get bright enough! On other phones, the user experience is designed so that the phone adapts to your usage -- at least, that's what companies aim for. It's nice because, when you want to use a feature, it is just there for you, ready to roll. To have to adapt to the phone - to have to go through extra steps to then arrive at a worse experience -  is just a weird change that is not just unwanted: it turns me off of the phone. Having to use a smaller display along with pressing the switch screen button is a pointless and shockingly tedious change from other phones that far outweighs the initial coolness of the form factor. The functionality outstays its welcome, and in the end, it's just not worth it. There is yet another issue with the cameras: unsurprisingly, they aren't that great. Their outputs are very soft, lacking almost any fine detail. That essentially means that even without a beauty mode, it will be super soft and look as though there was a (poor) beauty mode filter. So, let's recap: you must physically turn the phone around, going out of your way by manually flipping the device, to access a poor camera setup on a terrible display. If there were any other advantages to the form factor, such as the inclusion of useful features that I'm currently not able to conceive (but hey, that's their job, not mine) then maybe, these compromises wouldn't sting this badly. But I doubt it. This is definitely the flashiest way to achieve a full screen, bezeless front, and it's also the worst I've used.

Nubia Z20 vs OnePlus 7 Pro Camera Samples

Beyond the dual-screen gimmick, the Nubia Z20 is entirely average and not really an attractive buy. It is interesting and definitely an eye-catching product, but there really is no incentive or advantage to this design. The front display on the phone is fine, but the usability of the phone is compromised when you have to go out of your way or go through unnecessary motions to use something as basic as the camera. Even with the good specs, it just doesn't feel like a compelling buy.