Short answer: it is godly.
Longer answer: there's been a bunch of discussion already, take a read through the following, and if you have any further questions, feel free to post in this thread again, or one of the others.
TIVO or Cable company DVR?
TiVo
Tivo?
TIVO- Good, bad...any advise
ps: If you do decide to get one, there's a referral bonus going on right now. I'd love if you would use my email address when you sign up for the service. PM me if that is cool with you.
pps: My advice would have been the same with or without the referral bonus thing, but free stuff is free stuff...