My screen turns off when power supply charging if I push a button and bring up the menu. It won't for USB mode.
I think my screen looks pretty good, except it makes blues look a little odd. It oversaturates it or something. The colours aren't quite as vibrant as my PC screen, but I can only tell if I hold one next to the other when they display the same picture.
My unit doesn't go off when charging, but I wouldn't say that my screen is particularly good. OK for videos, but blurry for text and emulators.
That's because of how the pixels are arranged. They are set up in a kind of "diamond" pattern which is designed for video playback. I don't mind it for most games, as it kind of makes it look like it's being played on an old TV and it helps to mask the scaling. But I can understand why people would prefer the "grid" arrangement.
(If someone knows the technical terms for these screen types, please tell me).
How are the pixels arranged on this "good" screen?
Here's something I found on Booboo's blog
The LCD is a "delta matrix" type. Don't know much about the technology (I'll appreciate links), but it basically means that the color dots are not aligned in an orthogonal matrix but spread in a zig-zag pattern. This is supposed to be better for displaying pictures and video, but I think it's not good for games.