I've just got my 930. The screen goes black during calls. Have to press the power button to bring the screen to life, but it disappears after a second. Impossible to make a call which requires you to press the keypad for options!
I still have the original protective plastic that came with the phone, as I haven't bought a case yet.
I moved from Apple to Windows, because I prefer the software. But having the a visible screen, to be able to do simple things like press speaker phone or do something simple as use the keypad (which Apple does flawlessly), should be a basic need for a mobile
phone. It's ridiculous