I just picked this one up last week. It's a SIG Sauer PM400 SWAT pistol with the SB15 Sig brace chambered in 223/556.
It's got an 11.5" barrel and it weighs 6lbs unloaded. I'll probably go with an Eotech XPS2-0 since I've got Eotechs on a couple of my black rifles. I haven't decided on a sling or a light yet, but I've got time to figure out how I want to accessorize it.
It came with one cute little neutered 10 round magazine
I think it looks much better with a standard capacity mag
here's a shot of the back of the gun and the SB15 brace
The gun comes with copies of two letters from the ATF stating that the brace does not make this gun a SBR therefore requiring a $200 stamp, and a 5 - 6 month waiting period for approval. The overall length of this gun is 28" which also makes it legal to attach a vertical fore grip (26" being the minimum)
The other nice thing about it being classified as a pistol is that in PA. it is legal to keep it loaded in your car (as long as you have a license to carry a firearm), something you can't legally do with a long gun.
I haven't had a chance to get it to the range yet, but hopefully that'll be soon.