While I would disagree that the film is "totally unique" (there certainly are many "de ja vu" moments), it certainly is an amazing example of a spiritual police / gangster drama, full of surprising, pleasant subtleties, a pair of extremely complex and unusual leading characters, amazing form (the cinematography was stunning, imho) and a minimalist, but fine score by Wojciech Kilar and, to top it all, probably the best car chase in recent American cinema (those who have seen the film will surely know what I mean) which, altogether, made my decision to include it on my TOP 20 list of the year. This sujet definitely stood in the rain within the last few years and this finally was an effort which, to me, was easy to praise. 
(This post may seem a little empty but I already had an extensive and exciting discussion with A and Matalo Matango)