Their customer service is top notch in my book. One of the main reasons I stay with them, despite debacle with iphone/apple/data caps.
The only time I had a problem with AT&T is when a dude in the store who didn't know anything (he was new), tried to tell me I had to call CS to resolve my issue. The issue at hand was merging a friend's Go-Phone acct into one of my family lines. Well when I called CS, they told me that it had to be handled by a store. HOWEVER, instead of leaving it at that, they went and hooked me up with a different store in the area and told the store I was coming and everything. THAT store then helped me resolve my issue.
Overall I love AT&T's customer service, I know for a fact my mom had nothing but problems when she was with Verizon. In fact I called up AT&T CS just yesterday for an unlock code for an extra phone I have. No problems whatsoever, took less than 20 minutes.
I recently went to the AT&T store in the Providence Place Mall to place an order for an iPhone 4 and pick it up. Great service each time.
Also, AT&T must have been doing some work locally here because I am getting close to 3 mb down and over 1 mb up on the speedtest.net app. I'll take that.