Well, if you listen to the fanboys at dbstalk.com, they're the best thing since white bread. OTOH, if you listen to the other fanboys at the Tivo Community Forum, they're absolutely terrible. Why not use it for a while and form your own opinion. I've never used the HR20 or HR21 personally so I have no real opinion either way, especially since I dumped DirecTV for FIOS.
Please don't PM me or any other members looking for personal assistance. You'll do better by posting (after you've exhausted the search feature, of course) and taking advantage of the collective expertise of the membership instead of a single individual that may or may not be able to help you. Thank you and enjoy your stay at DDB!