Underrated
I really see IMDB rating so off the mark. If you're put off by the low rating and wonder if you should see the movie, see it. Take my word for it. It's 100% believable - the three lead characters did a great job, and so did the director/writer.
Like it or not, one thing for sure - you'll believe every single minute of it. And that's what makes a movie a great movie.