When I was in the Reserves, we would travel all over and go to remote places, and still have to communicate with each, i.e. use our cell phones. In almost every case, Verizon Phones were the last to go out of coverage and NOT get a signal. Its NOT just hype, it really does seem Verizon does have the best coverage nation wide.
BUT, if AT&T covers you just fine where you will be using it, then that might NOT be as much of a factor.
I'm fairly dissastified with Verizon's high prices and their policies, like disabling built in features of the phone, and charging you a monthly fee to turn it on and then its usually a Verizon version of that feature. The high monthly fees for data plans, and NOT allowing you to get certain phones unless you add a data plan to your package, which this last year, verizon has moved just about all their phones to the catagory of having to pay extra for a data plan to be allowed to upgrade to the phone.
NOT sure if AT&T and others are as bad as Verizon in those respects, might want to compare them all before deciding, because IMO Verizon has some drawbacks even if they have the best coverage, I just don't know if the others are the same as well.