It is really between Sprint and Voicestream in my area. All the others suck. Here is something that you should note, yes, voicestream does have exellent call quality, but they round to teh next minute. So, if you make an 11 sec. phone call, it counts as 1 minute. But on Sprint, they round to teh next sec, so if you make a phone call for 11 secs, it counts as 12 secs.
Voicestream has very good marketing tactics. 1000 min, right? Wrong, those 1000 min are distrubuted between you anytime and week end minutes and your regular minutes. So you are basically going to get 500 anytime any where min, and 500 weekend min.
You should also note that Sprint is one of teh only companies that do not require a contract, and Voicestream has a pretty dull selection on phones.
Overall, I like Voicestream, but Sprint does have its advantages.