As a generalization, I've always been attracted to both movies and books, I think for different reasons as I look back on years of reading and movie watching.
A book sets up a scenario and lets my own mind create its own screen and its own sound system of voices of characters and commentary from myself, a rich world behind my eyes when I am very involved with a given book. The flow of the words on a page adds another layer (or if badly written, takes away a layer, if not makes me stop reading) - giving me not just the voices of the characters in dialogue amid the developments of the story, but the sounds of the sentences, sometimes joy in the exact choice of words.
A movie that I like will pull me right into space, the space of the action, or the space of the conversations. There will be visual depth of field and movement within it, changing frames of color compositions at high speed, changing implications of the last action, or the action before that one, with variations in the speed of all these changes. It is a ride, really, whether through a small intimate setting (My Dinner with Andre) or vast panorama (Dr. Zhivago, Days of Heaven).
So, it seems to me that some stories work out best as books and some best as movies - and that there is an intersection where a story could be told well by either or both.
I ran across a book that probably preceded a movie I once was crazy about, Ivan Passer's Cutter's Way; I think the book was called Cutter and Bone.
Anyway, I read the book after the movie and found out a lot more about the characters, naturally enough. I liked the book a lot too. But the movie is what has stuck in my mind all these years, for several specific visuals, for the light in Santa Barbara, for the acting, for the music, which was a little unusual at the time, involving a glass harmonica.... My memory is of being there in the movie with them all.
I suppose many writers and directors re-work the story in a way that is less satisfying than the book, that some of the new scenes are just plain dumb, and that the actors might not be so great. Script, direction, acting, all being pitfalls of any movie.
I guess I am getting at that the book and movie should be judged for their own values.
Cutter's Way