We have DirecTV with Tivo.
I assume your parents already have DirecTV or are planning on getting it? (satellite/etc..)
Yes, the set ups are the same - some variations in the remote, but all the options are the same.
And this is something new I learned from a friend. (probably an advantage of DirecTV w/ tivo)
We have a 40 hour box as does he and he was complaining that it never stored more then 20 or so hours. (he has regular cable.)
apparently - DirecTV satellites transmits in mpeg format (or something like that) and it's stored at mpeg. cable is analog, so the 'show' must be converted to mpeg...and you have 'qualities' to record at - the higher the quality, the more space it takes up on the HD. (so 20 hours of TV would take up 40 hours of space.)
we LOVE our Tivo. We ran a second line from our satellite so that we can record 2 shows at once (or watch on, record another). We're actually getting a second Tivo for our bedroom. (yes we watch too much TV)
oh - another plus with DirecTV w/ Tivo. It's a flat charge a month added to our DirecTV bill...I think it's $5...and we don't pay ANY extra for additional receivers. (so when we get the second tivo, we won't have to pay any more a month for the system.)
the DirecTV w/ tivo boxes are relatively inexpensive..we bought ours in March (a Phillips) for $100...I think DH said they are around $80ish now?
hope that helped!