My brother called this “Ocean’s 11.5″.
I was disappointed by 12 — having the plot be a pointless, artificial contest was, in my opinion, a big cop-out by the writers. Also it was a bit incoherent at points, with a bit too much dialog left implied.
13 takes a stab at avoiding these problems. The plot is about revenge, old-fashioned but still fun. The dialog and situations aren’t quite as hard to follow (though I did spend much of the movie wondering what a “kooker” was, only to find out, via a review, that it was “cougar”, which luckily the review explained).
In the end 13 was a bit formulaic, but I could watch the cast of the movie all day long, and it was enjoyable enough to recommend. I own 11 and 12 and this one is comfortable enough that I’ll probably buy it someday and watch it when I want an easy distraction.