What sort of velocity and muzzle blast do you get from .357 SIG in that barrel length?
I think I'd lean toward a P-239 for concealment and P-226 for open carry or more casual concealed carry. But I can carry Gold Dot Plus P 124 grain ammo or HST in that bullet weight in 9mm. I no longer work for any organization that specifies what I can carry.
Our local cops carry SIG's and .357 SIG is an optional caliber, the norm being subsonic 9mm. I'd certainly want a .357 SIG if I otherwise had to rely on 147 grain 9mm.
It doesn't bother some, who don't even know or care which ammo they have. I asked one officer and he had to call home and ask his girlfriend to look at his spare ammo in the closet and read off the bullet weight!
Another, much more "into" guns, carries a P-229 in .357 SIG and said that he and others agitated the chief until he reluctantly allowed .357 SIG as an option. One point they made was that .357 Magnum was okay for officers still carrying revolvers.
The new M-11A-1, an upgraded P-228 with a milled slide and other improvements, strikes me as an appealing gun. I gather that it will gradually replace aging P-228's in Naval aviation and various Federal LE organizations, like NCIS and Army CID. But it has a cheap looking tag on the frame that looks like a price code for register checkout! I've seen this gun only in photos. Can that tag be peeled off or is it pressed into the metal?
I'd only buy a SIG with a milled, stainless slide, due to the tendency of their pressed/stamped slides to rust.