Apple Thoughts: T-Mobile Supports iPhone: Something They Don't Sell

"When a system update caused service failures and bugs in T-Mobile customers' unlocked iPhones, the users emailed T-Mobile to alert them to the issue. Even though T-Mobile doesn't offer the iPhone, they fixed the bugs and gave the users a service credit for the inconvenience."

You can say what you want about the guys in Magenta, but they know how to keep customers happy. They always have, and they always will. In fact, I'd hazard to say that they're one of the few companies who put customer service ahead of pretty much everything else, and that isn't just my opinion... JD Power has agreed for years.