I'm not the kind of person that hates a movie if it doesn't follow the book exactly, but in this case there was a lot of stuff missing I thought was important. I felt like there wasn't enough between Ron and Hermione and the end was missing things I felt were important.
The movie was fine, and I thought the acting terrific. The director and art people's style in the movie was just lovely; a lot of nearly black and white scenes with a focal point of red (like Schindler's list or Sixth Sense). All in all, it's definitely worth seeing, but if you haven't read the book you'll miss some good stuff.