I would be wary of anyone who likes this movie a little too much. There's so many effective elements that overall cohere into a gripping thriller, this film really does revel too much in its "Non PC" attitude. I get that, in many ways, it's aping Tarantino, not only in its quick-talking-hitman plot but also his use of offensive, taboo language. You really get the sense from Tarantino, though, that he at least *likes* the groups whose language he might offend - I don't get that from Martin McDonagh. It really just seems to be three straight white men doing things like asking midgets if they want to kill themselves because they're a midget.
The characters are very well fleshed out; good thing, because there's so much dialogue and so few actual characters. This makes the eventual climax legitimately pulse pounding and ultimately (mostly satisfying). Like I said, though, this movie is liable to turn a lot of people off with its misogynistic, racist, bigoted language, but if you're able to look past that, you will find a strong film.