Well, I already covered this one last year when it came out, and I don't have much to add to my original thoughts. I've watched it at least one other time before this time, and I have a little more appreciation for the ending (the payoff for Hoffman's story is still underwhelming, but the climax for the insurance adjuster's plot is more entertainingly nuts than I originally gave credit for). I now think it's probably the 2nd best sequel, after part IV, mainly due to some slick cinematography that makes the movie more colorful than any of the others in the series (the editing is still a mess, though), and the film's silly, yet spunky, stab at social relevance.
I had, at some point, some half-baked plan to watch the entire series in preparation for Saw 3D this weekend, but that's just not going to happen. 3D is supposedly the final installment (which normally would sound like a bullshit claim, except the films have made increasingly less and less money), so I'm seriously hoping they pull out all of the stops and make a ridiculous gorefest of never-ending plot twists and absurdity. Fingers crossed.