All I know as far as LEO use with Sigs in my area is that many of the Chesterfield Co police officers were starting to have serious issues with their Sigs after approx 500 rounds. They wound up trading them for G22s (according to an officer from that dept). Who knows, maybe its a fluke or maybe there is some recent underlaying QC issue. Either way, if its a factory refurbished SIG with a sub $400 price tag it might be worth it.
Personally, I've never really liked the balance and bulkiness of any of their handguns.