I like the phone for the price, however for me personally I have 2(3?) gripes with the phone that stop me from using it full time. I'll try to list out some pros/cons though overall.
Pros:
1) That all screen display - Its awesome, just looking at this phone with the screen on in person is something to behold. I wish more phones would look like this from a screen / bezel perspective. (regardless of how they choose to hide the camera)
2) The cameras are really good at this price point, especially the front facing camera.
3) If you use the Xiaomi.eu ROM, this phone is quite stable and notifications actually work as expected. I don't have many complaints on the software side of things when using the .eu ROM.
4) The overall build quality is really good for the money you're paying it feels very premium in the hand and only waivers slightly when you touch the top of the screen (and notice it flex's because of the gap, which is necessary!) or the slight side "wiggle" ill mention in the cons below.
5) Works on Verizon in the US! (Global Version)
Cons:
1) Overall weight of the phone - While from a dimensions standpoint its about the same as my Pixel 2 XL, the Mix 3 weights about ~43 grams more than the Pixel 2 XL, which is quite a lot (its ~17g heavier than even the Note 9!). If you have smaller hands, this thing becomes tiresome to hold for more than short bursts.
2) Slider Construction - While overall I like the slider itself, there's definitely some play (at least on my phone) where the screen can "wiggle" from side to side, especially when its slid down. This is almost completely eliminated when the included case is on, but if you dont use the case its definitely noticeable and can be annoying.
3) Vibration motor - It's realllll bad, and it doesn't help that with the screen "floating" above the body because of the slider that the vibration rattle is even worse. As someone who leaves their phone on vibrate only, its kind of annoying.
Other Thoughts:
1) I really like the full screen gestures, I just wish the swipe "back" target area didn't go so far up (maybe only the bottom 25-35% of the screen). It makes it hard to use apps that have slide out menus (think the play store, gmail, etc.)
1.1) For the swipe to go back gesture, it kinda "forgets" the last app if you go to the home screen. So the swipe and hold to go back to the last app only works when you go from one app to another that isnt the homescreen. Not a deal breaker but kind of half-baked on Xiaomi's part.
2) Using the Front Facing Camera, if you have small hands, can be a real pain / require two hands when in use because of the length of the phone when the screen is slid down.
3) Google Voice match AKA "Ok Google" or voice to unlock is currently broken on the official Global Stable & from what I can tell the .eu rom. I don't really use it because of the dedicated AI button, but YMMV.
4) I mentioned this in another thread but the pop-up for "slide down to use camera" is obnoxious, so if you use Snapchat a lot this phone probably isn't for you.
Do I recommend this phone?
At this price? (currently in the US $500-550) maybe. If you want a more polished experience, I would definitely get the OP6T instead, while you miss out on the full screen display, the really good front facing camera, and wireless charging, you get a better overall android experience, a larger battery, and overall less fit and finish issues. HOWEVER. If you absolutely cannot handle notches this phone is probably the best option.