Seriously, don't be on the poster. Pretty much everyone on the poster gets whacked. I had done my crude maths on this one. It was a heist movie, and I like heist movies. It was directed by John Hillcoat, who I hear good things about. It had loads of good actors, mostly the kind of unflashy non-stars that I like. It looked like a safe bet.
And in a way, it was. It's pretty much the movie it sets out to be, and the performances are solid. But it's not fun; if your heist movie reference baseline in The Italian Job, this is going to be a bummer for you. And if your baseline is Heat, as of course it should be, you're going to be holding Triple 9 up to the light and saying "Meh, no. I should have put Heat in the DVD player instead."
Amazingly, the Georgia State Film Commission helped out in making the movie, which makes Atlanta Georgia look like the other Georgia during any of its wars; random gunfire all over the place? Check. Russians behind it all? Check. At least when Yorkshire hires itself out as a war zone, it tells everyone it's Nordor. Other fun fact; the bank they rob at the beginning looks just like the hotel John Wick stayed in, and I'm just going to believe they were the same place, even if IMDB insists that they're not.
Everyone is serious as all get out, except for Woody Harrelson, whose performance is most easily understood if you assume that no-one told him they were shooting in Atlanta and he thought he was in the New Orleans Police Department. Oh, and blink and you'll miss it, but that's Omar from The Wire playing Sweet Pea, one of only four female roles with more than minute in total speaking time (seriously, Kate Winslet gets more in than all the other women put together, and she's got about ten minutes total screen time).
There are some great set pieces; the opening robbery is cool, and it goes wrong really well. There's a ghetto raid in the middle which works great as a scene while doing just about nothing to advance the plot; it says a lot about this movie that the scene you'd want to keep is the one you could most easily afford to lose.
My abiding thought is that it shouldn't have been a heist movie at all. The Triple 9 in the title is the idea that cops drop everything if a cop gets shot (see, the opening of Bad Boys, which gets just the right amount of mileage out of the same idea), so if you want to do a robbery, drop a cop somewhere else and you'll have all the peace and quiet you need. What gives the idea its edge in this movie is that half the bad guys ARE cops, so they're figuring to drop one of their own to get the job done. And that on its own would have made a perfectly good movie, but instead there's a whole second movie about Chiwetel Ejiofor wanting to see his kid and make money from his very particular set of skills learned in Iraq. And that would also have been a perfectly good movie. The mistake was trying to make both of them at once. Not least because anything which gives Ejiofor that little to do is wasting precious natural resources.