I've just put Apple + Att to the test.
My family planned a "small" trip from Atlanta to Houston to be with our friends and family for turkey day. It was a 14 hour trip that stretched across a few states and I am very happy with the performance I got.
Around 80% of the trip I got 4-5 bars of 3G and the rest of the time full bars with Edge. My batery would last around 4-5 hours but I have a car charger here so it's all good
I happily surfed the web, listened to music, played games, texted and of course made phone calls. I didn't get a dropped call (running on 2.1) and even purchased our hotel before even arriving at the final destination!
All in all, I am very happy with this phone and Att's service. We are now driving back and around 9 hours out. Currently somewher in Louisana with 5 bars of 3G. I'm lovin it.

Around 80% of the trip I got 4-5 bars of 3G and the rest of the time full bars with Edge. My batery would last around 4-5 hours but I have a car charger here so it's all good
All in all, I am very happy with this phone and Att's service. We are now driving back and around 9 hours out. Currently somewher in Louisana with 5 bars of 3G. I'm lovin it.