I never read the books but what bothered me tremendously about the movies was the mucked up colors and digital grading. It looked so unnatural that it took me out of the movie. It was like having a different one of the component RGB cables not connected every 10 minutes.
Some scenes (usually overbrightened and having that painful Enya singing) were way overdramaticized.
The camera work during the fight scenes was atrocious. Don't give me this crap about trying to convey chaos, watch the battle scenes in slow motion. Notice how rarely the camera shows anything in frame much less in focus.