This is a harder movie for the non Harry Potter fan to follow as it expects you to know the back story. I liked the way they pretty closely followed the book, and enjoyed the performances.
Since this contains a lot of exposition, it's not as exciting as some of the other movies, but that's what this movie is about.
The biggest negative for me was the use of a jiggly hand held camera. I imagine that it was inteded to add tension or something, but I found it irritating.