If you're going from a series 1 to say..a 522.. you won't like the 522.
Tivo:
When you say, do not delete until I say, it doesn't delete
522:
Protected stuff gets deleted anyway
Tivo:
Season pass works
522:
Dish Pass is sorta there, but in a broken, crippled sort of way
Tivo:
Hack, hack, hack
522:
...
And so on and so forth. The 522 is less lossy due to the way it stores the programming, so the recorded picture does look a lot better, but the recording features more or less stink. It's not 'always on' so it won't keep a continuous 30 min buffer while it's off. Not so much a problem on the Tivo because who put it in standby anyway?
The Tivo's (especially the series 1 when you've hacked it a bit) are still the best DVR's around (IMO). You'll find people that swing every which way, though, because everyone wants something different. If you're die-hard Tivo, you'll probably be dissatisfied with recievers like the 522 and 510. I can't speak for the 942, however...