It's good. Better than "fine" but not "great".

Rating: 8/10 (21 August 2016)

Right off the bat the best part of this movie is the acting: Teller and Hill have great chemistry on screen. Jonah does a particularly good job at playing the "guy you love to hate". I can't attest to the faithfulness of their portrayal of the real life people since I don't know anything about them. The rest of the cast does a great job as well.
The marketing for this movie was, unfortunately, deceitful: the trailer made it out to be this upbeat, funny, over the top comedy - which it's not. In reality the movie has a much slower pace, not a lot of situational humor and is certainly not filled with hilarious quips (the bulk of which are in the trailer). This is not to say that the movie was bad or not at all funny, it just wasn't what I expected (and I am sure I'm not alone).
My final critique will go unnoticed for the majority of viewers but I found it personally offensive so I have to report it: some of the movie takes place in Albania, only the set for Albania is actually Romania. Which is fine, I understand that they probably did this for practical reasons and as a Romanian movie goer I just have to accept it (we all recognized it immediately though). However, at some point in the movie an "Albanian" woman says something, only she says it in Romanian. This may not seem like much but it totally took me out of the movie and ruined the experience for me. I find it completely unacceptable that they could not hire an Albanian to say those few lines. The two languages might seem interchangeable to the rest of the world, I am sure, but that was very much NOT the case for me and everyone else in the theater.
I am a paying movie goer as well and I expect to be just as entertained as everyone else. This is, of course, not the first time that I've seen this in a film. But when a producer does something like this it shows me that they don't respect their movie, so they can't expect me to.
My rating, however, is not based on this final bit of criticism. I gave it a 7/10 for slow pacing and lack of humor, which is the opposite of what I expected.
I'd still recommend it, just don't expect to be blown away.
After watching it for a second time I decided to change my original rating from 7/10 to 8/10, mainly because the acting is just great and I respect the fact that the movie made me think about it and made me want to see it again.