An early scene, involving the woman cheating on two guys, was very promising. That our woman was so fine also did help, and is the fact that the torture was on public display. This made it look like it actually had a fatter budget, and this got me excited. The only other moment that was well-done was the torture of the racist, and this is due to it's great production design and casting. The rest of the farce was worn out. Luckily the movie was more enjoyable than it's predecessor, Saw IV.
The whole premise of the series is actually interesting (though I sure hope no one would tries to imitate it), and I wish it was limited to the initial ideology, whereby the victims' decisions involved only them. But it seems to the writers that wasn't exciting enough, and there was instead an insistence on having it been done to others too, who were often innocent (e.g. you go through some horrid torture OR your wife dies). Sounds like desperate writing to me.
An earlier review of another in the series.