Yeah, I'm also in that tough situation. I purchased my first HDTV last year, and got TW Cable. At first there was a lot of skips and pixelation, and it took 5 tech visits until finally the last guy actually did something. It turned out the original tech left the screw ends of the cables loose.
After that, no problems for almost a year. My only problem was that the DVR only held 20 hours of HD video, which really isn't acceptable. I did some research and found that those Scientific Atlanta DVRs can accept external SATA hard drives, although officially, TW doesn't support it. So I got a 1 TB external drive and I was set for the football and new season for all my favorite shows. Well that ended around last month, when an update that was sent out to the boxes knocked out the external hard drives. I called them and of course they simply told me they didn't support that. I can either suck it up and accept it, or buy a TIVO box, or switch service providers. I don't really want to go back to satellite, so I guess I'll just wait and hope a new update fixes the DVR.
Their internet has always been outstanding for me. Pretty consistent 13 Mbps.