I don't really enjoy this section of the Grand Harry Potter Saga. In the first book, Hogwarts is this grand, mysterious place where Harry escapes from his horrible mundane life and learns to do amazing things and so on in an escapist vein like that.
By this point, though, things are just as miserable at school as they are at home. People are constantly trying to kill him and he's being sullen and not talking to anyone about his problems. Plus, the need to stretch all the plots out until the end of the year means he has to do stupid things (like "not practice Occlumency even though it's the only thing Dumbledore has said to him all year") to keep all the plot threads apart.
The problem with condensing a whopping big book down to a children's movie is that you either cut subplots entirely or shorten them into incomprehensibility. Like, that Occlumency thing I just mentioned is pretty much glossed over. And Harry seems to have some sort of flirtation with Cho Chang, except that it doesn't really take place on screen, so the only time we're reminded of it is when some character makes a reference to her, and then everyone forgets all about it for an hour.
The other problem is that they only condensed it enough to get the movie down to two and a half hours, which was too long for the child behind us to sit quietly through. Boooo.
I did enjoy Luna Lovegood, although I think I like her more in the books, where her particular brand of crazy gets more time to shine. I also liked the newspapers a lot, although I spent so much time trying to read the extra headlines, I sometimes missed the main thing I was supposed to be reading.