...I've had most of them as well...the worst being AT&T, second was Nextel (I'm part of the class action suit for overcharges for fed surcharges...haven't heard a thing for over a year).
In the meantime, I switched over to Verizon and the difference is immeasurable. I haven't "roamed" since I got it and though the guy in the commercials is a little chintzy...I always hear every call crystal clear.
If you are looking for specific models of phones...these things are upgraded so often it'll make your head spin...get the best deal possible. You'll find great deals if you want a flip phone sans the camera.