I am trying to decide between the Dish 721 and one of the DirecTivo receivers. I currently use a Tivo standalone (SVR-2000) with cable, and I am happy with Tivo. Is there anyone who can tell me the major differences between the two? I am mainly interested in the 721's PVR interface and how it stacks up. I haven't been able to find posts talking about Tivo's season pass and what the 721 uses that is similar (if anything). Opinions?