Today it is cloudy because I can not check how the device behaves in the light of the sun. However, my impressions are as follows. 12.3 beta 3 is another improvement but it does not eliminate stuttering in 100%. The first moments of testing were free of errors in operation. The device was charged to 67% of the battery. Then I connected the charger to this morning. Then, having 100% charge, WiFI connectivity continues the device works fine. Then I go to work, connect with the car and work ok. Now I'm at work the device has joined LTE, the e-mail application when checking messages, opening and closing does not work so smoothly. you can see stuttering. At the moment, so much the rest work ok.
Well, sounds like Apple's on the right path. You don't mention anything about video stutter though, do you have that at all anymore? Is it only the UI at this point?