Above all else, it is a beautiful movie: the lighting, cinematography, and especially the costumes are breathtaking. There were also quite a few scenes that were really fantastic, quite above par for most movies. The first scene with Telsa, for example, was simply delicious. The plot was also exciting--I really enjoy being shocked by a movie's twists. One twist was predicted by Katya ridiculously early on, but the other twist was a total surprise. There was one other twist that Katya and I comprehended (and appreciated) about a half hour before the end of the movie... but then it was "revealed" as the movie's final shot, making me wonder if it was intended to be shocking... or maybe just a meditation on "Nobody cares about the man in the box".
I was v. impressed with Bowie. I've seen him before, but he always was recognizable as David Bowie, more (Jareth the Goblin King) or less (Pauntious Pilot). Not that there's anything wrong with that--I usually have little to no difficulty in picking out Patrick Stuart, for example--but I have this notion that an actor isn't truly acting unless I don't know who is playing the role. I think that this is probably silly of me. At any rate, in Prestige he was completely unrecognizable (to me) with a fantastically convincing accent and an extremely compelling character. Go, Bowie!
My one caveat is that I did think the movie quite mean-spirited, which made me very uncomfortable. After they killed the first bird, I was constantly worried that they would show me something truly awful and surprising, or kill a cat or something.