I read the book first. Once I got over the made up slang language, it was fantastic. It’s description of dystopian youth is haunting but if you’d read it, you’ll know. Within five minutes of finishing the book, I watched the movie.
The book is better. Which is not to say that the movie is bad – but the book is better. No spoilers, but the ending that they cut out of the movie is good, the incidents in the book (girls in the record store, I’m looking at you) are far more disturbing in the book, and overall, it seems just more messed up overall.
But then again, the movie has “I’m singing in the rain.” So there’s that.