Our contract is about ready to run out with Cingular. We are probably going to stay with them as I really only have 2 choices them or Sprint. Alltell, T-mobile, etc. leave major coverage gaps around here. I've had a cell phone since about '94. Been through several carriers in that time including one of the first digital ones in the nation (Aerial - which has been my favorite service as far as reliability just not a lot of coverage it is now part of Verizon which uses GSM). I used to buy the top end phones and whatever went with them. But when I went with Sprint the first time about 7 years ago, I decided no more and took whatever they have for free or cheap and have been much happier now that $XXX phone isn't getting scratched or broken.
As far as service, I prefer the GSM much better than the CDMA that Sprint uses. At least around here it is much more reliable and a lot fewer dropped calls.