Alan Rickman is like bacon - everything is better with him in it, and the more the better. He steals every scene he's in, and has perfect the lordly stink-eye to such a degree that I think I'd be perfectly satisfied to watch 90 minutes of Alan Rickman condescending to people.
The rest is downhill. Oh, don't get me wrong - it's a beautiful movie, possibly even more stunning than the last few, and the casting is, as usual, dead on; Jim Broadbent as Horace Slughorn is particularly excellent and brings much of the non-Snape-related lightness to an otherwise very dark movie. The principles have come along nicely, maturing as actors as they've matured. (Particularly Emma Watson, about whom I can not say much without committing a felony. In my mind.)
But the pacing is weird and very stop-and-go. The film has few action scenes, and lots and lots of exposition, some of it deftly done and some of it rather plonkingly delivered. "Professor, tell me that important secret that we've alluded to several times, and explain it in a flashback, if you please?" In the end, it feels much longer than it is. What's more, John Williams is no longer doing the music, and the new composer (Nicholas Hooper) is thoroughly uninspired and uninspiring.
The movie differs from the book - I've always felt that Rowling never intended for Dumbledore to really be dead, there are so many howlingly obvious hints to it in the book that if she wasn't trying to set it up, her continuity is just dreadful. In the movie they had a chance to make it seem less suspicious, and indeed it is, even if it still doesn't make a lot of sense. It feels contrived; a wizard who is one moment putting down an entire zombie apocalypse in a raging inferno of hoodoo is not believably felled by a schoolboy the next. So boo for plot continuity.
The Director's Hall is a crock, by the way - while they will bring food to your seat, there's only one person in the entire theater running orders, and they're just slinging the same stuff from the concession stand anyway. What's more, they bring it in styrofoam containers that are incredibly loud and make scrunchy sounds. Add to that the fact that the people sitting next to me (who literally smelled like goats) brought their infant child, who fussed and cried through the entire movie, and I wasn't bowled over by the alleged "de-lux" aspect of the Bridge's Cinema experience.
Still, a fine movie and it's your nerdly duty to go see it.