I have used Comcast for my business and it was the biggest mistake I have ever made. When the service does work it's terribly slow but don't worry - most of the time the internet is completely down. This is due partly to the extremely cheap modems which constantly break and the low quality lines they use.
Do yourself a favor and stay away from Comcast if you can or if thats all thats in your area get a back up 56k service so you have a back up.
Pros: Sometimes Cheaper
Cons: Slow speed, always down, cheap modems, terrible customer sup
more