There is a reason this question comes up so often, and it’s either a good reason or a bad reason. Either we as readers have made “book movies” so profitable that studios are doing them more than they used to (the good reason), or books have gotten crappy enough that “book versus movie” is finally a fair fight (the bad reason).
What’s probably happening is a hybrid of the two—we as readers have made crappy books (every Hunger Games knockoff, also The Hunger Games itself) so popular that movie studios are doing them more than they used to, which is forcing even more and more even comparisons between the two formats.
And when we talk about book movies, we all agree that we are talking about “book movies,” right? Like, The Social Network is not a “book movie” of “Accidental Billionaires,” is it? Argo is not a “book movie” of a New Yorker article, correct? Stuff like Under The Skin and Children Of Men are in a grayer area, I guess. (Wow, a lot of movies are technically based on books!)
Anyway. I liked the book and the movie of The Green Mile about the same amount. I liked the movie of Catching Fire better than the book. I liked David Fincher’s Girl With The Dragon Tattoo better than all previous iterations of that story. The Fault In Our Stars is a better book. The Wire is better than “The Corner.”