I have Tivo w/Direct TV, 2 boxes. I pay about $75 a month which was so much less then my old cable bill. We have tons of channels too. I can Tivo up to 40 hours on each box.
You can only Tivo 2 shows in the same time slot, and you can't change to a 3rd channel to watch something else. Also, be aware of selecting times when you Tivo, especially if it's something you are dying to see, the ending may not tape if the show runs a minute or so over time. You can set Season Passes to Tivo every show then you can make adjustments to your season pass by only Tivo'ing first runs or adjust your end times so you are sure to catch everything.
The only other problem I had was my Tivo box dying on me twice, we sent it back after they sent us a new box each time, but going through the person on the phone to explain the problems, get put on hold, talk to someone else, get transfered to the next tier support person, etc. was a real pain in the ass. After the third box came we had no problems.
Just be warned a lot of companies use refurbished Tivo boxes, we knew they were refurbished/used by the exterior condition of the box and then we had the problems. With satellite TV/Tivo the picture comes in through one box which Tivo is inside so we had NO TV/TIVO when we had problems.