Just came back from the theaters, watched the whole thing in IMAX 3D whathaveyou, and I have to say, I am immensely pleased with it.
I didn't feel it dragged for a single second. Sure there are some slower scenes, but they're appropriately paced given the circumstances. I was on the edge of my seat the whole time.
I am also very satisfied with the radically changed ending.
The book's ending was incredibly disappointing and anti-climactic (if you think this movie is anti-climactic you probably haven't read the books), and the changes made here make for a much more satisfying (dare I say, sensical?) conclusion to the saga.
If movie-going wasn't so stupidly expensive in this country I'd probably go again.
As a side note: they're showing Prisoner of Azkaban on TV right now, and the contrast is striking.
The older movies, the first 3 to be precise, are decidly more playful and...childish?...if you look at the later ones.
Pointless things like Harry blowing up his aunt and the bus for stray wizards seem almost uncharacteristically light-hearted for the series if you consider how it all ends.