Saw it yesterday and thought it was brilliant. I think overall it's better than Shaun of the Dead, mostly because of the ending, which kept building up more and more, unlike in SOTD, where it sort of tapered off. Having said that, it did seem like it was ending and then something else came along, like in Return of the King. Other than that, very good.
I'm wondering if Pegg, Frost and Wright have a third type of film up their sleeves. Science fiction maybe? Not sure what else they can do...