The impression I got when looking for a TV last fall/Winter was that the TV had more to do with the quality than the provider, and the providers were more or less in a pissing match with each other.
I got a great huge DLP in a deal before Christmas, and the picture's gorgeous. It's the best hockey season ever for me, as far as game clarity. I'm anxious for a full NFL season now with it. Like I said, we're Comcast and everything's fantastic through it, and hardly ever any issues at all with all 3 services (and I live a very hilly/mountainy and rural area where trees are in lines and weather sucks). I think if you're happy with your current service, stick with it.