I'm particularly impressed by its ability to let you 'rewind' as far as the buffer will let you (OK, I know that's not unique), but then, it lets you start recording from the beginning of something that's happened up to an hour ago. It's proved useful on more than a couple of occasions when my wife has poked her head round the door, with one of those 'you might have told me, I'd have liked to have seen that' looks on her face.
From a 'hobbyists' point of view, its ability to run TAPs is a brilliant idea.