I have Sprint... and to be perfectly honest, back when I got it around 3 years ago, the main reason I went w/ them was they were the only company that didn't want to charge me a deposit
They had a pretty good phone selection at the time (I started out w/ an A940) and they had decent family share plans. I've stayed with them because the coverage and service is generally good in my area and until recently, never really had any issues w/ their CS.