I feel I would have understood more of the movie if I had known more about Tron. With no prior knowledge, it was somewhat technical and a little difficult to follow at times. Nonetheless, the graphics were great and it was a very fun movie to watch. It is also definitely one of those movies you should try to watch in IMAX 3D! It was a great experience!
I have seen all the movies and read all the books, and this is the best Harry Potter movie so far. Splitting the book into 2 parts was such a good idea..I finally felt like I wasn't running through the books in order to be able to fit everything like the other movies. The books are very long, and to be able to fit everything, they usually end up cutting out a lot of the small stuff that makes Harry Potter so wonderful, and then changing a lot in order to be able to have the movie still make sense after cutting out everything. Not this movie - they stayed much more loyal to the book and it worked so well. For those who said it dragged a bit - that's the point. If you've read the book, you know that's how the first half of the book is as well. All in all, it's the first Harry Potter movie I left fully satisfied!