which cell phone carrier?

<p>hi guys.....i'm wondering which wireless carriers, like att verizon sprint t-mobile, have good coverage at cmu? i've heard that tmobile doesnt have 3g service in pitt...
and how's the customer service of these national carriers?
and is the $30-ish/month unlimited data service necessary at CMU, with 100% wifi coverage on campus and 99% of the students w/ computers?
lastly, are any students on family plans with other students for a lower average fee?
thanks guys! i'm coming to cmu this fall and i want to know which carrier the students use the most...</p>