Pros: Yeah, you can accumulate a lot of rollover minutes. This is the great thing.
Cons: Although they advertise that the minutes don't expire, they do. Also, you DON'T GET TO KEEP THEM ONCE YOU HAVE PAID FOR THEM.
Summary: I have been with Cingular for about 3 years now. I started with a plan of 2100 minutes per month. Well, I realized that I wasn't using as many minutes as I had planned and had accumulated over 7,000 Rollover minutes, but when I tried to lower my bill by decreasing my minutes, Cingular said that they would have to take over 6,000 of my "already paid for, you paid for them so you keep them" minutes. When I asked why, no one, NOT EVEN A MANAGER COULD GIVE ME AN EXPLANATION. So, if you plan on going with the company please ask for clarification about your minutes. Oh, and by the way, the minutes do expire...One year after you roll them over, they expire.