I have an iPhone 4S on AT&T, and this thing has NEVER switched to the Edge network. Even in areas of poor coverage where it doesn't get a 3G signal, it always sticks to the 3G network. I was just out in an area where it didn't have good coverage - in fact, the phone popped up a message saying "Cannot connect to cellular network" - but for some reason it said "3G" the entire time. It never went to "E". Why is that? My old iPhone 3G on AT&T had no problem switching to E. Now I have the iPhone 4S on AT&T, and I still live and work in the same area, but it never switches to E when it can't get a 3G signal.