T-Mobile is retooling their network to give HSPA+ speeds to iPhone users. This should be done by the end of the year. I am considering leaving Verizon for their bring-your-own device plans with my iPhone 4S. These plans are around $45/mo for 5GB data and more voice and texts than I can use. The only thing holding me back is their insistence on getting me to sign a 2 year contract. I've been on Verizon for 10 years and know nothing about T-Mobile's level of service. I would not want to lock myself into a contract with them without the ability to leave at will.