The Harry Potter movies, in my opinion, are geared predominantly (99%) at the child audience, while the books are written in a way that anyone can read it and enjoy it.
The movies in my opinion, do no justice to the characters. They do not develop them very well, it seems like their's something lacking every time and I can't really connect to the characters in the movies as I can to the book characters.
The only movie adaptation of a book, that I've been totally happy with, has been Peter Jackson's epic, Lord of the Rings. Although there was some changes, it was an excellent portrayal none the less.