I just got back from the screener for SAW.
It's not all the time that you leave a theatre with just a whole lot of "OMG WTF WOW" type feeling... but that's just what I got from this flick.
If you like tense, horror, suspense, gore and twists... you'll love this movie. DONT read up on it, DONT read a spoiler... You definately want to go into this movie with an empty brain.
Anyways, I wouldn't recommend it to non-horror fans... it's definately a bit gruesome. But if you like to be scared and challenged... watch Saw.