I've got TWC with a HD8300DVR. Channels 2-98 are analog, and very good. 99-140 are digital, and although they are 480i, have outstanding pq, as is the sound. Channels 701-751 are HD (although there are only 7 HD channels at the moment). I don't pay for extended HD coverage.
Discover HD is perfect. I just wish I got Fox and ABC. Some areas have it, some don't. If your set has a built in ATSC tuner, I highly recommend an in attic/roof antenna to pick up the free OTA HD channels.
The reason we didn't go with Dish, was that we have a tv in 6 rooms, and all are hooked up to cable. 90+ channels in every room for one price is nice, and we can lease a DVR box month to month if need be. Plus with Roadrunner, the price is fair at under $82 which includes 800 long distance minutes. My folks have DSL, which is much slower than cable. I don't think I could go back.