TMobile service is great in big cities. When I go home its 1g and Roaming(free). The real nice point is the great prices and excellent customer service. Today I called to see when my upgrade date is and I had a person on the phone and was done in 1 minute.
T-Mobile also has a policy of unlocking subsidized phones at the request of customers in good standing. 90 days? Paid your bills? Just call and ask. Done.