I am a traveling sales rep and travel throughout the state of michigan. While i find that Tmo doesn't have the coverage that other carriers have in my state, the price is by far the best. The blackberry service is outstanding, and even though Tmobile says edge shouldn't work where i am at, it works flawlessly. It is much faster then the GPRS.
Big picture is yes i am happy with Tmobile service. Oh yeah and when i call a customer serivce rep i actually can understand what they are saying! (not foreighn)