When I first sat down to watch this show I was expecting another formulaic, "fast and loose with the rules but always just on the right side of the line" cop show. I must admit that I was pleasantly surprised.
Dark Blue is indeed refreshingly dark; the characters are predictably tortured souls with an interesting mix of personalities and histories that add to the depth of the plot lines, they are all superbly written and acted to the degree that sometimes the plot becomes something of a happenstance as we follow the personal journeys of the protagonists.
the plots themselves have all been seen before in numerous guises, but Dark Blue puts a new and slightly twisted slant on them that can fool you into thinking that you have never seen them before, but it is worth remembering that the case is not really the important thing here; it is what the case does to the characters that defines the show.
All in all, I would recommend this show to anyone who wants to watch a new and gritty take on a genre that has not yet been pushed to these limits.