Well, it can't be compared to the Saw series (totally different styles; I absolutely adore the Saw movies though).

I just watched it for the nth time these past few weeks and I'm still dangerously close to explosively and involuntarily emptying my bowels after every jump-scare and spooky scene. My girlfriend, on the other hand, has a constitution that's built for horror movies. She hardly flinched the first time we watched it together.