What's wrong with a carrier model? We love our TMO iPhones.
Locked to T-Mobile under EIP; they have to unlock it for you upon request. It only has an Intel modem, which cannot be used on CDMA carriers. Resale value isn't as nice as the CDMA/GSM models. T-Mobile also isn't fair to long time subscribers with their new "deals" since you have to add a line and/or trade devices in.