I used to have Comcast. I had nothing but problems that they were never able to correct. Internet would drop out randomly during the day. Would be off for a few mins, hours or days. When I would call them because it was off for about half a day, they would do there worthless diagnostic from the office and always tell me the connection is working fine. They said they would have to send a tech to the house, and won't be 4 days till they come out. So of course I'd be without internet for days, then it would randomly come back on. They then would not come out to check it since they said it's working and nothing can be done if it's working at that time.
We changed over to a complete SBC package now. "Premium" DSL, Satellite Dish TV, and digital telephone. Much much cheaper for all together in one package and never have any problems at all with my connection. SBC's DSL configuration is a joke however. Piss poor software installation and hardware provided for connection. I requested a standard DSL modem and they gave me 2WIRE Home Portal garbage. I sent it back, ignored all there bullsh*t software install and configured everything in the modem and my router manually, and never had a problem.
I've done many on-site installs for DSL though and had nothing but problems using there software. They constantly change the software too, so everytime you learn one, it changes on the next CD release.
So it's either I'm stuck with slower but reliable DSL or get Comcast's high speed which never stays online and pay 3 times as much. It's crazy how much Comcast controls and you really don't have a choice on service besides them.