Love this show. There's a very small set of shows that I've liked enough to watch all the way through multiple times: Halt and Catch Fire, Max Headroom, and Person of Interest are pretty much it.

As others have pointed out, it starts out as a somewhat run-of-the-mill police procedural type show, but starts to evolve into an awesome sci-fi show part way through season 2. And the last couple of seasons are an amazing sci-fi thriller about competing ASI's. I personally can't recommend it highly enough.