Why does anyone care what carrier the OP uses? The amount of "EDGE mocking" is insane... I bet all of you loved EDGE back when iPhone 2G was out 🙄
He wants an unlocked phones and there is nothing wrong with that. In fact, fully Unlocked phones are higher in price when being sold aftermarket. Also, if he travels overseas, there is no need to do unofficial unlock and play "cat and mouse" game with Apple on every single software update.
Personally, as mentioned before, I would purchase these fully unlocked iPhones as well if they have the white color but alas. I would NOT use T-Mobile, rather I will sign up for a no commitment AT&T. That being said, there is nothing wrong for using T-Mobile and pay $59.99 for 500 minutes + unlimited data + unlimited text + no contract.... as opposed for paying $69.99 for 450 minutes + 2GB data + 200 sms + 2 years contract + 5000 night/weekend minute.