I have 2 Tivo's we love them so much. They MUST be connected to the Internet to get the guide and from what I have seen this is more accurate than the broadcast EPG. There is no ongoing subscription (in Australia).
http://www.mytivo.com.au/ if you want to know more.
It's best feature is the season pass. Tell it to record a show and it will record it even if they move the timeslot.
It also tries to learn what you like and if it gets bored starts recording similar shows for you. I have caught many shows I would otherwise have missed like this.