Hurley is the top of the police-procedural hierarchy. I find Rankin a vastly overrated self-publicist, and many other police procedurals are ho-hum at best.
The key to Hurley, as another reviewer pointed out, is the sense of place. My father was a cop in Portsmouth, and the atmosphere, the language, the description and the sense of sneering, striving desperation is spot-on.
Allied to this, Hurley's characters ring true, and he is prepared to leave a crime unsolved, something many others in the genre would do well to attempt.