I forgot to mention....
No problem with proximity sensor.
If I hold without case (lefty) my hand covers antenna gap and signal drops from 3 bars to 1 bar. However, I always use a case to protect phone so I have no reception issue when using case.
No yellowing screen.
I upgraded from original iPhone. On the way to the Apple store yesterday I tested the cellular download on Edge vs the new phone on 3G on the way home. Original iPhone ranged between 25kbs - 110kbs on SpeedTest app. New iPhone ranged from about 500kbs - 2100kbs. I'm very pleased with the speed improvements going from the Edge network to 3G.