Overall, I liked it pretty well, and think it didn't seem as rushed as some of the previous films. It's difficult for someone who's read the book NOT to evaluate the movies in terms of what they left out, but I suppose most of the stuff that they omitted wasn't strictly necessary to the plot. In fairness, I'm sure it's a real balancing act condensing a long book into a reasonable-length movie while not contradicting it in any significant way. I would have liked to see more of Tom Riddle's past and some scenes of Snape actually TEACHING Defense Against the Dark Arts, but you can't have everything. Besides, if I remember correctly, most of what we got from Snape's class in the book involved non-verbal spells, which turned out not to be particularly important anyway. Then again, why was it necessary to throw in the scene with the Death Eaters burning the Weasleys' house? And since when is Lavender Brown a white girl? For that matter, I still haven't gotten over their changing Flitwick for no apparent reason.
One thing Beth mentioned after the movie was how mild the scenes in the cave turned out to be. Dumbledore's reaction to the potion was much less severe than it sounded in the book. It was supposed to cause him severe pain, while it just came across as mild distaste in the film. Along the same lines, I noticed that the results of Sectumsempra were nowhere near as gruesome as Rowling described them. Maybe this was just to keep the PG-13 rating, but they made the scenes less intense than they really should have been. Also not particularly intense was Hagrid's mourning over Aragog.
And, well, that's probably about all for Harry Potter until the next movie comes out.