I love the Harry Potter books and movies, so I'm probably pretty biased. But they've set the bar pretty high, so it is easy to be critical.
If you've read the books, you'll immediately compare them to the movie, and find many flaws, because due to time limitations, they left out things, or didn't develop others, to your liking, and that is my biggest complaint. They introduced the character Loony...I mean Luna, and gave her very little background. You never know her dad runs the biggest gossip newspaper in the witch world, which explains some of her oddness. I also didnt think that they gave the true feel of how isolated Harry Potter was during the school year. And they also skipped the part where the centaur replaced one of the teachers. Those were my three major dork complaints.
But for the most part, it was wonderful. Great visuals, acting was great, and the girl who played Luna was great! Jenny Weasley was part of it all, and unless you know who she is, you don't realize it. The CGI was great, the special effects...all good. They do such a great job with the lighting to set the mood...you can tell they take great care with their work. One thing you will notice, Harry has stopped growing, while Hermoine and Ron Weasley have kept, so Harry is now the shortest of the three.
I could go on, but I don't want to ruin any of the story. It's not my favorite of all the movies, but I did like it more than the last one. I'll give it 9 broomsticks out of 10