In my last 2 residences, I had no problem with Verizon, and big problems with AT&T. In both locations, missed and dropped calls on the AT&T network were common. Additionally, I never see the 3G icon displaying on my iPhone in my home, and this morning I could not email 4 pics from my iPhone to my wife. They are still sitting in my out box.
I had a dropped call with a client earlier today. With Verizon, I rarely had any issues. I would pay 2x to have this phone be usable to me.
I've had the opposite experience. And T-mob customer support is far nicer.
It may be , though, that what works best depends on the particular region. Still happy with their customer support; they helped me in assorted ways and it was quite pleasant.