This reviewer pretty much sums up my experience:
The acting was superb and Mamet's direction was typically good. But the film's "B movie" architecture forced it to resort to the lowest common denominator of moral and ethical messaging. This was nowhere more prominent at the very end, which finished in a very strange, hardly believable, over the top homage to some literary notion of purity and honor (As a side note, the depiction of jiu-jitsu is nothing like jiu-jitsu in the real world as I've come to understand it over the years. I suppose that doesn't really matter for the story, though).
I thought I would want to see this movie and it is by no means bad or unwatchable. But it isn't much of anything. The ethical underpinnings of the theme are hard to swallow in the format Mamet's uses, which makes me wonder altogether if the type of movie Mamet was after can even be created using MMA as the subtext. So, go see it if you have a free afternoon, but I left questioning what others saw in a movie that was rich only in accouterments.