Before I would look at particular models of handguns, I’d make some criteria...
First, what type of holsters are you authorized for and what security level will you use?
In my case, we are currently mandated to select from an approved list of firearms, all of which have a manual safety which must be engaged while in the holster. Our two approved holsters are level 2 retention. The department is considering (and has already pretty much decided) to remove the manual safety requirement...but has not said anything about approving holsters with higher retention levels. At this point I would not carry a handgun with no safety in a lower retention holster. You have to evaluate what level of retention you want on the holster and the gun itself. For example, you may want a simpler weapon (such as a Glock) with greater holster retention, or a quicker draw with more safety features built into the gun.
Do you want an external safety?
If yes, Glocks are a No-Go unless modifications are authorized. If not then most of the manufacturers you list offer DA-Only variants.
Do you want extra safety gizmos?
Smith & Wesson 3rd gen. Pistols mostly all have magazine release safeties. Cool for weapon retention, bad if you have to shoot a round and have no mag. (Mags can get accidentally released...Not totally common but it happens.) P7's have the squeeze cocker...It is a neat system but takes practice and may not combine with otehr weapon systems well.
What caliber do you want?
I like the .45, and carry a USP .45 on duty. I think the 9 is fine, however, and if I was mandated to carry a 9mm I’d be OK with that. (I often carry a 9mm P7M8 off duty.)
Capacity...Is it important?
Most will tell you that you don’t need more than 8 to 10 round mags. WELL...I’ve reviewed several shootings that involved a much larger round count. Not for bad aim either. Now, it’s most certainly a law enforcement “running towards gunfire” thing. (Hopefully one would not place themselves in a situation that could deteriorate like this while off-duty or as non-sworn.) Maybe it’s a Los Angeles County phenomena, but if you are in a fight with a guy who has an AK or SKS, you may have to employ suppressive fire. Maybe your initial shooting encounter gets the locals pissed and ready to go, or maybe there are suspects working in concert so you’ll have to deal with multiple suspects from different directions. You will have to evaluate your area and potential for these scenarios when you select your weapon and your spare magazine holders. (I carry three spare 12rd. Mags on my belt and two more in the bail out bag. I know many deputies who carry 4 spare Beretta or HK magazines on their belt.)
So now I’ll comment on the guns themselves:
Berrata: Model 92, Model 96, 9000s Type F
I like the Beretta. It is our issue weapon. It is accurate, reliable, and durable for what needs to be done. It is large, and it is DA/SA with a safety. There are those who will find it too large for their hands, while others will find it very comfortable for a DA 9mm..
Glock: 17, 19, 21, 22, 23, 26, 27, 30, 31, 34, 35, 36
Glocks are great guns. Simple, reliable, exceedingly durable. If you like ‘em, go for it. All models listed (except sub-compacts) would be great duty guns.
H&K: P7-H8, P7-M8, P7-M10,P7-M13, USP-9, USP-45, USP TAC-45
I carry a USP45 on duty and a USP45C or P7M8 off duty. I really like them. Recoil is minimal, they have been 100% reliable, and very accurate. I also like the position of the USP safety...It’s a DA but it’s as close as I can get to a 1911 in an approved weapon. (And have a few extra rounds to boot!
Sig Sauer: P220, P225, P226, P228, P229, P239, P2340, P245
Another good gun...No safety so use tactics and retention accordingly (as with Glocks)
Smith and Wesson: 410, 457, 908, 910, 3913, 3953, 4013, 4053, 4513, 4553, 4043, 4006, 4046, 4563, 4583, 4586, 5906, 5946, 5903, 5943, Model 99
I carried a 4506 for a while and really like them. I wanted more rounds, the USP feels a bit more comfortable, and after accidentally releasing the mag in the holster, I didn’t ever feel totally comfortable with the mag-release safety. I’ve heard reliability horror-stories but all my S&W’s have been reliable. (I have a 4506, 4566, 3913TSW, and had a 6906. All 100%.)