I liked the book better than the film, and I actually saw the film first. It has more depth, and has so much more than just the romance, which is depicted way lot more in the film. The way Matthew Quick wrote Pat's POV allowed my reactions to connect and sync with what Pat was feeling at different moments of SLP. When Pat is happy, I find myself smiling, and when Pat is in pain, I find my eyebrows closing on each other. The great thing about this fact though, is that it never completely sends me to both ends of the mood scale. I did not whoop around in my room with estatic joy, or bawl buckets of tears reading this and I appreciate that. 
 Full review here: Blog