Sometimes I like movies based on books, sometimes I don't. I'll usually have one of three reactions.
One of them is that I like both the movie and the book for different reasons. For How to Train your Dragon, for example, I like the movie 'cause Toothless is adorable, I liked the story despite how familiar it is, and dragons. I like the book because because it has Stoic's full name, which I can never remember, it was a short, but enjoyable read, and dragons. Did I mention that I like dragons?
One of them is that I like them both, but I'd rather simply watch the movie 'cause I don't have time to read the book. Examples are The Chronicles of Narnia: The Lion, the Witch, and the Wardrobe and the animated Charlotte's Web.
The last reaction is simply "The book was better." Examples are the live action Charlotte's Web and The Chronicles of Narnia: Prince Caspian.
I probably simply don't read enough books that have movie adaptations, but that is all I got on the subject.