It was... good.
As good as the others and a touch more confusing. Which is the point.
I liked the second one better but the third one and now #4 make you think about the "worth" of life in a strange kind of way.
And that, I think, is the "horror" part of these movies. Not the blood and gore, but the fact that after a while you start to sympathize with Saw and his helpers. You see how there is a method to his madness and how his "work" makes sense.