Overall I loved the artistic license that the movies took to make things more beautiful. In PoA, Harry's ride with Buckbeak was a much more magical, beautiful, and incredible moment than just flying around in a circle above the class. I actually watched all the movies before reading the books, because I knew the books would probably ruin them, but I was shocked that Jk Rowling doesn't really write much for your mind's eye. All she ever  said about the Hogwarts Express was it's "a scarlet steam engine." Wow. It's no wonder people get upset, because they've had to fabricate so much while reading and it's probably nothing like the movies. I will always appreciate how visually beautiful they are.