I have both Verizon with an HTC Touch Pro 2 (Windows Mobile 6.5) and I'm on a friend's AT&T plan with an iPhone 3G. Verizon's data plan is faster. It just is. I see all these graphs about how AT&T's 3G is the fastest, but I don't see it. I don't know how you AT&T guys can browse ColumbusRacing on AT&Ts 3G. Wifi is fine, but when I'm out of the house it's unbearable.
When I drove to Cincinnati, I tried using the iPhone Sirius/XM app. About 30 minutes after leaving 270, the music started dropping. I picked up the iPhone, and it's on Edge. I think it's just a small patch and it should come back soon, but nope, I think I got my 3G back when I got to Mason, OH. My Verizon phone on the other hand, 3G all the way, but no working Sirius app for Windows Mobile. Also, my church camps twice a year in Danville, OH. Absolutely no AT&T coverage. On Verizon I get 1X at least.