Went to see the advance screening last night at IMAX. Here's a rough overview:
First off, everyone should try to see it there. It was amazing to watch on that screen.
Cuaron's fingerprints are all over this thing. From the opening scene where we find Harry playing with his wand under the covers to the shaky cinema verite camera work in some of the scenes it's obvious he's at the helm. There's also alot of stylistic references to Spanish surrealist cinema, which was great. It's much darker overall. The sky is constantly overcast and everything on set seems dirtier and filled with shadows.
Some things have changed, Hagrid's hut is in a totally different spot and some of the architectural elements of Hogwart's are different. Most notably the clock, which I don't remember being in the first two, serves as a constant backdrop.
The CGI is outstanding, especially the dementors. They are so bad ass that I almost crapped my pants. They couldn't have been any better. Buckbeak is also very well done.
David Thewlis is great as Lupin. His mentorship of Harry seems realistic and heartfelt. Oldman is great as Sirius Black but one of my major complaints is that he doesn't get a great deal of camera time. I guess that's just the nature of this story though.
My only big complaint is that I feel that Harry's emotional development, frustrations, etc. aren't fully developed here. I mean he's obviously getting pissier, conflicted and angry but the feelings behind that aren't really explored. I would like to see that come to the surface, especially in the next two films as his black and white world becomes gray.
So all in all I give it 4/5. This is easily my favorite Potter film so far with it's dark style and rich CGI. Fans will be jumping for joy as they leave the theatre.