sprint probably has the best coverage and phones but their contract committments and requirements suck. Tmobile has good plans and decent phones but sometimes their signal is not very good in common areas. Verizon has got a pretty good system set up with good coverage, phones, and plans. I would probably stick with that. But check them all out. US cellular ain't bad but I don't know many people with it.
in my experience, att/cingular and sprint suck in chicago and verizon is the best (my friends who have verizon always get reception when i dont and there are no instances in which ive gotten reception and they havent). funny that you're switching from verizon....i think im switching to verizon!
I would stick with Verizon. I have never had trouble with it in Chicago or in Champaign Urbana. There is a crappy spot along I-57 near Kankakee. Reception is pretty bad but if you are in the cities you shouldnt have trouble. I also advise considering the service of those you call often. My best friends are all on Verizon. When we talk all the minutes go into our mobile to mobile minutes; just something to consider.