verizon hands down is better
at&t doesn't even come in here...
I have tmobile...theyre hit or miss but Ive never had cust svc issues and their 4g is suddenly better, i don't think they even offer iphone tho
the other half has verizon and he seriously has amazingly awesome perfect reception always...he has a droid now tho...
upside is for basic business stuff verizon is pretty easy to tether to your laptop and the 4g is about the same speed as dsl at least