as far as i know the on demand/catch up is currently exactly the same ... though this may change over time
the only real advantage i can see is its search capabilities are greatly improved and can even search online content though i suspect that will be heavily restricted to which sites and providers
other than that as far as i can tell its just newer hardware that works better and faster (which you would expect from a newer device)
others with Tivo will be here soon to promote anything I have missed
