Really liked the first one, second was also really good.
After that it became almost too disgusting, and maybe I'm a bit soft but I think the gore stuff takes away the genius from the movie because I get a bit thrown off by it.
I remember after watching SAW 3, I sat so pushed back into the chair that after the movie when I stood up I got cramps in my shoulders and neck.
But you've got to acknowledge the most often absolutely genius twists in the end of the movies.