I think the movies were pretty true to the books. The casting was excellent. My middle daughter is a Harry Potter fanatic; she went to the midnight preview last week, and.... dressed up
for it. She won a Hermione Look Alike Contest at a Harry Potter Book Release Festival about 5 or 6 years ago. (One of the towns outside Chicago turned their entire downtown area into "Diagon Alley" for the release of the last 4 books or so. It was amazing.
She's... grown..... She said the last movie was the best yet.
I've seen the movies and read the books, but she's the real expert on Potter-ology in our house. Our little one loves the books as well, but not with the enthusiasm that her older sister does.
I haven't seen the last movie yet. But, so far, I've been happy with what they did. As close to the books as any movie ever was, IMO. I'm glad they made the last book into two movies as there was too much going on to fit into one movie. I think the people who made the movies put a lot into it to make it true to the books.