Misery- No spoilers please!!

I'm just wondering what everyone's opinion of the book Misery is? I'm just over half way through it and I am struggling to keep picking it back up. I just feel as though it's not as suspenseful as his other books (or it isn't at the moment), and it's quite slow plot wise. Normally I can't put a SK book down! Without spoiling it, can anyone tell me if it gets better/ more interesting???