T-Mobile says no 4G = no good.
AT&T's got the iPhone, and now so does Verizon. Furthermore, the CDMA version of the iPhone on Verizon gives hope to Sprint also getting it on its CDMA network. So which company is left out of the reach of the iPhone 4? That would be T-Mobile.
T-Mobile operates on the AWS 1700 MHz band, which has not been supported by any iPhone to date. Is T-Mobile bothered by the fact that it doesn't have the iPhone and that the nation's two largest carriers do? Yes, probably. But it's not showing it. In fact, judging from the new TV spot below, T-Mobile doesn't seem to be minding much at all.