I saw it last week and I thoroughly enjoyed it. I'm not a fan of romantic films or horror, but this was neither and yet both at the same time, which is why I liked it so much. It's a zombie film with a heart, literally and figuratively. It's also got a witty first person narrative from the main character's perspective, and the actor makes R's character so lovable.
I give it a solid A.
Just saw it tonight, and I have to say I agree with Gryffindorian. Though I might knock it down to a B+/A- because it suffers from the all too common rushed ending that most Hollywood fair suffers from today. Overall a most enjoyable night at the movies.