Horror stories keep you on edge and make you want to know what will happen next. Mystery stories keep you thinking and make you want to finish the book fast. Both are very "teeth grinding" an make you want to finish the book. But horror stories are more about emotions, and mysteries are more about things that get your brain going. I prefer horror stories because of the way it makes you feel, from angry to scared to sad, horror stories are deffinanty uch more exiting.
(Mysery vs. Horror on Mrs. Gs blog)