No current Dells have a yellow screen, so I have no reason to think that this one will be any different.
Dells also have traditionally had great battery life, though VGA is more battery intensive then non-VGA screens.
As for thickness, might be thicker then the 4150 but it doesn't look like by much. But it's got a nice curved back which looks very comfy to hold in your hand
I have to wait and see the price though....but either this or the X30 will be mine!