All providers have coverage weaknesses which result in dropped calls in certain pockets.

T-mobile is the only provider I've ever seen with chronic fundamental problems (calls getting crossed, voicemail not picking up, network busy messages, etc.).

T-mobile also doesn't maintain their own netwok, so they're second-tier to any carrier they buy from. They also seem to have more capacity issues than most carriers.

Sorry, but it looks like I'm helping to validate Mrs. Frugal's concerns.