You're seeing these captioning problems on ALL of the channels? Is there a difference with captions on HD versus SD channels, or for different kinds of programming?
You might try checking the quality of the caption data by running the RF cable directly into your HDTV, assuming it has a built-in QAM tuner, and making sure your TV's digital captions are on. (You may be able to get at least some channels.) If the captioning is still buggy on digital channels, then the captioning is either being badly transmitted by your cable company (which is common) or by the program distributor. If it's flawless, then there's a problem with how your cable box is set up or how it's designed.
BTW, what kind of HDTV did you get (since you liked the TV's CCs?)
