Lots of different considerations as a cop I think Archy and Bramdawg.....What is your departments most carried handgun, 9MM, 40 Short and Wimpy or 45ACP ? If everyone is carrying a 40 Glock I'd look at that caliber for one reason and that is the ability to share spare mags if the situation should arise.
Myself I would suggest the new 45GAP as it comes in a neat durable glock 17 size package, it's a short clone ballistically to the 45ACP and I am pretty taken with my G37 (magnaported later) I have had for about six months. I have ran about 2000 rounds through it without a burp or chirp and it's very easy and fast on failure drills of two to the chest and one to the noggin.
I suggest the combat tupperware for cops for one reason, durability to carry 12 hours a day on duty, stands up to wear and tear and no bells or whistles and with a good security duty holster which I think Big Ern can help you with makes a very comfortable rig. I'd take a serious look at that caliber and setup for LEO work.
Key in my opinion is to bring what ya can hit with and if that is a 9MM or 357SIG then sobeit . Hits are all that count when muscle memorymatic pucker factor kicks in. If ya can't hit then caliber, make model and cool factors are all BS......
Hits under duress are prime consideration for choosing a sidearm . Hope I gave ya something to think about as you make your choice as it is YOUR choice ya have to live with....
Stay safe !
If I had my druthers,I'd walk around with an AR-15 if they'd let me. Thats where I get really dialed in 8>)