FWIW, I have the fiberoptic service from ATT (Uverse) that they recently introduced to the Memphis area. The speed is great (get much more than I'm paying for). I've had it for about a year now and have never had an outage. I also have the TV package with them. The picture quality is great. The couple of times I've talked to customer service people, I've been more than satisfied.
Comcast, on the other hand, always delivered speeds that were well below what I was paying for, went down quite often, and the digital TV picture was mediocre at best. Don't even get me started on their "customer service". I was more than thrilled to cut the cord to them! Sadly, I have to deal with their crappy internet on the computers in my office and for the server that our work PDAs run off of, but at least I know I'll have good service when I get home!