It's a regional thing; where Comcast is concerned, I think it really depends upon where in the country you are. Here in New England, I have never had any significant issues with them whatsoever. I'm quite satisfied with them and have no plans to switch, even though some of their competitors charge less.
Comcast in other locales, however, can be downright terrible. Florida Comcast locations, for instance, are notably bad in my and others' experience. Almost everyone I know in Florida has had very bad experiences with Comcast. Additionally, one of my phone lines has a Florida area code; if I happen to call Comcast from that phone line, I am connected with a Florida location, which ALWAYS offers far worse service than when I call from a New England number and get connected to a New England call center.
So, take that for what it's worth.
(Mind if I ask where in the the country you are?)