I'd rank them like this , in terms of *consistently good* quality episodes
Elite tier:
Fringe (if this qualifies as a police show, not in the traditional sense but it really does kick ass)
Criminal Minds (this show is back near the top by focusing in on really disturbing cases and not so much on character backstory/drama/blah)
L+O:SVU
Southland
Good tier:
CSI:NY
NCIS (this show is going downhill fast, very hit and miss lately... although the characters are still amusing)
Cold Case
Meh tier:
CSI:LV (I thought adding Fishburne would turn this show around, but not at all. This is very mediocre nowadays, the best episode in the last 2-3 seasons was a Star Trek convention parody. Enough said)
L+O:CI (was much better before recent cast changes)
Bones
Numbers (was much better before all the "action" elements added the last year or so)
Crap tier:
Mentalist (honestly don't like this enough to really rank it, but the few I saw were abysmal)
CSI: Miami
enough saidCopRock level of suck tier:
NCIS:LA
Although they aren't "crime procedural" type per se,
In Plain Sight and the upcoming show Justified are looking strong as alternatives to reruns of most of the above during the year.