.
I see a lot of you are for verizons 1GB for $20.00 plan. But since (as you said) I can easily change plans from month to month, I think I'll give AT&T a try. And if I find myself in need of more data, I'll go with Verizon. Because 4 times the data for 5 more bucks is a LOT. Not to mention better coverage.
So more than likely I will end up switching.
Amy I'm afraid you'll have to make this decision up front. The data technologies (cell spectrum etc) are different so you either buy an AT&T or Verizon version, and cannot switch without getting a different iPad.
(You can upgrade or downgrade plans with either one, but not change carriers)