I really hate it when someone asks me if I liked the book better than the movie. I hate it because they get really confused when I tell them I don't compare the two. When they go on to let me know that they thought the book was better, they get even more confused when I ask them "why?" They stutter about how this was left out and that should have been done differently, etc., etc., etc. Usually coming up with no real GOOD reason why the book was better.
Almost everyone seems to do it. Critics, writers, readers, people on the street, and they almost always say "the book was better." Interestingly, the one time in recent years when the movie was very nearly a scene-for-scene shoot of the book, the complaint was that the movie was too much like the book! ("Harry Potter and the Sorcerer's Stone"). I've come to the conclusion that most people really don't care whether the book or the movie was better. They just want something to complain about.
I used to compare the two. I gave it up. Comparing books to movies is kind of like comparing apples to broccoli. No comparison whatsoever. Two totally different media. The three movies that make up "The Lord of the Rings" are a favorite target. The most popular complaint I've heard around here is that they really wanted to see Tom Bombadil. Yeah? So leaving him out made the movie awful? (Yes, said some.). Peter Jackson had good and valid reasons for leaving out Tom Bombadil (and some other scenes). Those reasons mostly had to do with time constraints and that the scenes in question did not move the story forward.
Among some of the lay people, that is not a good reason. I have had to point out that in order for Peter Jackson to have placed EVERY SINGLE SCENE they liked in those movies, they'd be sitting in the theater for a lot longer than three and a half hours per movie.
This is why I don't compare the two. I know that some of the fun scenes in a book will be cut because they do nothing to add information and they don't move the story forward. Yeah, I like those scenes; and yeah, I'm a tad disappointed that they aren't included. But, I also know that there's no way the powers that be will allow every single book that is optioned to be made into two or three movies (just to get the WHOLE story).
Yes, I occasionally will make comments about movies when I've already read the book. Mostly, those comments have to do with casting (I either don't like the actor, or I like someone better) or with some things that I "saw" differently in my imagination. I will continue to refuse to be caught up in the argument over which was better.
The answer is: Both.