I recently tried out Comcast cable TV in the bay area. The DVR they gave me is a horrible piece of crap. It would crash or freeze about once a day, and after rebooting it would take 20-30 minutes to reload the program data after a reboot. It would record the same episode over and over, even though it was set to new episodes only. The list goes on but those are the worst of it. I assumed I had a bad unit until I found this site: http://www.bernzilla.com/2008/03/08/the-joys-of-using-a-comcast-dvr/
Turns out they have been giving this same awful DVR to customers FOR OVER TWO YEARS. They knew it sucked, but continue to give it out. When someone complains, they replace it with another of the same. That is seriously crappy service in my opinion. Luckily my place has just barely enough sky view for DirecTV. My fiance and I seriously wanted to smash the Comcast DVR with a hammer after a week.