USP .45, nothing wrong with 9mm but it is far more capable of overpenetration, and you didn't list any other HK's. Reason for picking one of the most costly guns? Police hardly fire their sidearms on duty, so why not put all of the money you would spend on unused ammo, towards a gun that is ultra-reliable, I know Glocks are too, but I have heard bad things about sloppy lock-up, as well as about the trigger, ergos and grip angle.
SIG's are heavier than most other guns listed.
Ditto with 1911's, plus, they tend to have a break-in period, not to mention being 101 years old. It also shares the XD's over-the-edge flaw, the grip safety.
Beretta 92's are heavy for what they are packing, plus the excessive size, and exposed barrel, I am not it means less slide to manipulate.
Literally nothing wrong with your average revolver, but they could leave a LEO undergunned against someone packing a semi-auto
"|Pistol calibers| all suck, so pick the one you shoot best."