Ready Player One is a decently good movie. Scott Pilgrim vs. The World is in my top 1% movies of all time and I've seen at least a couple thousand movies. To me there is no contest.
Edgar Wright is brilliant with this movie. I've seen a couple of other movies he made, and while they are decent, they are nowhere near as brilliant as Scott Pilgrim. (If someone knows another E.W. movie this good, then please tell me, but I don't think it is any of the Simon Pegg ones.) The visual storytelling in this movie is the best I've ever seen, and of course the script is also brilliant. Michael Cera is probably not cast right, but that is the movie's only flaw to me. On the other hand, they somehow found a whole bunch of people who are now stars, and I think most of them were relatively unknown when they were cast in Scott Pilgrim. The movie oozes originality, and it was made in a time when it seemed that Hollywood had run out of ideas. (It still seems that way in fact.)
I'll take Scott Pilgrim for the win!