AT&T prepaid is ok...i've had them for over a year now, the 90 day to 45 days expiration is rather frustrating..but what do you expect, AT&T is raising prices for all their services across the board practically, no matter phone service, broadband, wireless ,etc.
For the $16 something a month if you renew with $25 cards, it's an ok deal. If I was on a plan I would be paying at minimum $20/month before taxes, but if the taxes are added in (around $3 total I think?) it's a pretty good deal for those that don't use the phone too much. I also like it because AT&T has a very large coverage area in the midwest, and having the Nokia jump onto different networks is definitely a plus (the only times I've seen no service on my phone was briefly while in the Ozarks, but that is understandable). Oh, I also saw no service in south dakota's black hills, but hey..that's also understandable. For my home calling area there are no dead spots for miles so it's just fine anyways. I have never been disconnected from a call either..which is awesome.
The last time I renewed the phone tho was a bit of a hassle, since the automated credit card over the phone thing didn't work...then I got dumped over to a rep, who charged me another $25 afterwards, and gave me the minutes. Luckily I never saw the charge go through for the automated system (I did see a charge for a couple days but it dropped off the bill, I think it was just an AUTH charge)