I wish I could complain
I have little problem with AT&T's data network. EDGE works great for me in all locations, and I consistently get satisfying speeds on 3G (up to 3Mb/s in many cases of testing and long downloads.) Mind you, I do not use an iPhone and my experience is limited to my home market, Atlanta, Little Rock, and Memphis.
One thing I have noticed in my home market, however, is an inordinate number of dropped calls in the past couple of months. More than I would ever have in a year. I have had to switch back to my EDGE phone while I sent my 3G off for repairs (stupid backlight,) and this is the most problematic my service has ever been. But I called and reported it and have been given some pretty good information about the network in my area.
Customer service, that is definitely the ticket. I have complained about AT&T's approach to phones before (poo poo support for unlocked phones, secret root certificate to sign applications, and the transition from TDMA to GSM/GPRS, to name a few.) But any time I have called with an issue, AT&T was quick to work to resolve it and make me happy. I have received more than one phone call from their executive escalations, and I have always walked away smiling.
There have been a couple of times I have considered moving from AT&T. But I like my phones, and next to T-mobile it is the only "game in town." Right now I certainly do not have any compelling reason to leave. I feel like a lone twat in a sea of twits when I cannot join in the bitching.
Paris, poo poo support.