I live in a different area then you, so my experience is super helpful, but I'll share, AT&T has always been faster and had better service in my home town. We actually switched to AT&T for two reasons 1) They were getting the iPhone 2) Verizon didn't have service at my house
Both of these are o longer the case, but we've had no reason to switch back to Verizon. AT&T has been great both network service wise and customer service, the only issue is a few overly friendly customer service, but honestly, that's not really a bad thing. And while I have had to push and stay firm at times to get what I wanted, AT&T has always come through. Not to mention we've done an early upgrade with them about three times before I contact was due for an upgrade.
And recently their put LTE in Washington DC(where I go to college), I've picked up a HTC Vivid and I've been loving it, sooo fast because so view AT&T are on the network. I understand it's not a large network so far, but it does a great job where I spend 8 out of the 12 months of a year.
Also I love the control I have with sim card, going so far as to own multiple phones at one point, which is great to try out and take advantage of what each OS has to offer. Not to mention I have a large pick of device, as I can shop outside of the carrier store.
AT&T's network is much faster then Verizon's both in theory and from adecdotal deviance I've collect in practice. Other then LTE, which speeds should be the same in theory, although I imagine more Verizon's users are own their larger network, which means while more people are covered, you risk more crowding leading to slower speeds(although I don't know if that has happen to Verizon's LTE yet) but they are both quite fast) While Verizon has more LTE coverage, that's only useful if you travel a lot, it you don't, your local network is far more important(at least in my mind)
Also AT&T has far more HSPA+ coverage then Verizon has LTE coverage, and in some areas and with some devices, HSPA+ can reach or surpass LTE(although it's unlikely at this point).
It would take a heck of a lot of wrong doing on AT&T's part to get me to move away from them, even then, I'd likely go to T Mobile and if the merger of AT&T and T Mobile happens, I'd look for MNVOs that run on GSM before I went to Verizon. It's a preference thing, the technology is better in my view.(although I'm glad Verizon is moving to LTE, it's just going to be a while before one can depend on just GSM standards on Verizon's network, while AT&T is all GSM today)