I had AT&T during 1st year, and was able to talk on my phone anywhere in the building, outside, and in both parking lots. A friend had Sprint, and her phone only worked by the door on the first floor. This was true of another friend who had Sprint too. During 2nd year, I switched to Verizon (the "why" in a minute), and my service was spotty, if available at all. I couldn't make any calls in the building or in the parking lots, and there are only a few spots on the lawn where it worked. I dont' know anyone who has T-Mobile, so I dont' know about their service.
As for why I switched from AT&T: My contract started on Jan 2, 2000, so you would think it would expire sometime in Jan, 2001. It expired on Dec 19, 2000. After that, I still had service, but they had me on a "month-to-month" plan, which costs 25 cents a minute. I did not get a letter about the cancellation asking me to renew or anything. Convenient for them that they raised their rates on me without telling me just before the holiday season when I presumably would be using my phone more. This happened to a few of my classmates too when it came to the end of their plans. So be careful with them, they like to change things, and they probably do send a letter, but they send so many letters about this and that credit card, frequent flyer program, home long-distance, new phones and gadgets, etc. that I probably threw away the letter because it looked like the other junk.
Doc Oc
UNECOM 2005