Well I don't know for me it has been well worth it I paid 99 bux for my Tivo and 149 for the lifetime and I have upgraded my HD a couple of times when the old one has given up the ghost.
So all said and done my Tivo has cost me $ 350 for the last 5 or so years not too bad.
I just wished that it would do 5.1 but that's another story