I've had AT&T, QWest, Sprint, and Verizon. The best advice and information I ever received from this site was to go to Verizon.
AT&T used filthy business practices, had terrible service, below-bottom customer service, and their equipment kept failing. Qwest was a nightmare, dropped calls constantly, had poor connectivity, couldn't get their billing straight (something in common with AT&T), and continued to bill me for a year after I had dropped their service and closed the account. Sprint made all sorts of wonderful promises, including the advent of free roaming...but didn't bother to tell me until after the first bill that it was only free if at least half my calling was in a sprint area.
I do a lot of remote calling, and my first bill was hundreds of dollars, even though I'd only used a few of the minutes.
Verizon, using one of their least expensive phones, has been phenomenol. Their service is good, even in remote locations...forgetting to turn my phone off, I've had calls come through inadvertantly at very high altitudes, too.
The equipment is tougher than nails. The qualcom phone (LGT or LGB or something like that) was on my hip this new-year's when I was struck in the driver's door by several cars. The phone was crushed against my hip, and the top part shattered, including the outside screen. It still worked like a charm for a few months until I could get to a place where I could replace it. I couldn't walk...but the phone was up and running. Can't complain about that (as far as the phone goes, anyway).
I'm very pleased with Verizon.
I'm pissed enough with AT&T that I gave the phone to someone else, quit paying the bills in order to let the service lap, and decided that they can go to hell for all I care. They extended the contract repeatedly without authorization, changed rates, switched to roaming during calls and charged me for it...and hit me with eight hundred dollar a month bills for making calls within my published service areas and during the allotted hours, within my allotted minutes. Let them take their payment in blood, because they're not getting it from my wallet.
I'm quick to pay Verizon on time. I like their program.