We have had Comcast tv and internet service for seven years and have seen improvement in that time. The cable used to go out fairly often when we first got the service and it would take several calls and some waiting for things to get back up and running.
Their phone help used to be very spotty but has improved. You could tell that some of the employees were just reading from a manual and the minute you describe something that wasn't on that page, they bumped you up to a supervisor. That could take up a lot of time. But things are better now---we call much less often because the system works better and when we do call we get more knowledgeable staffers.
The service center is great---had to replace back remotes twice and they just gave us a new one each time, no questions asked. No waiting, either.