While I plan to be as non-specific as possible, some of my comments, when seen in the context of the film, may be spoilers. Joker has written a more spoiler-specific review
on his website.
I once read that the long con is an urban myth, the stuff of movies. It depends upon a series of contingencies that could cause it to fall apart at any moment. But, I like con movies, so I make allowances. I assume that the con men have alternate plans B, C, etc. However, the con that is at the heart of Matchstick Men
is dependent upon so many wildly uncontrollable variables that I'm going to suggest that, to the extent people are actually surprised by the ending (which is broadcasted in a dozen different ways), it's because the con is such a bad con. And that's cheating.
In fairness, though, Matchstick Men
is far more interested in its characters than its con. Which is fine, I guess, except that the story of the guy whose life is changed by meeting the child he never knew he had has been done to death. Here, the characters are reasonably well drawn, it's well acted and not terribly cloying. The interaction between Cage and Lohman is interesting, but the relationship between Cage's and Rockwell's characters is not very well developed. We're not sure why they're partners and we don't know if they're friends.
There were a fair amount of laughs. So, on the whole, a good film, not great.