Yep, I'm mostly a handgunner too. Down here in the southern part of the state, deer hunting is shotguns and handguns only. I carry a Ruger SRH 480. Once in a while I will carry my Ithaca model 37 with a red dot on it, and a SBH .44 as a backup. I've had trouble with my shoulder and find I can more easily carry a pistol than I can a rifle/shotgun for a long day of hunting.
I do have a Bushmaster AR that I primarily use for plinking and target shooting. At some point I want to go after coyotes with it, but have not gotten around to trying it. The idea of turning it into a thumper deer gun seemed like a fun thing to do.
I'd love to hear from some people who have actually bought one and shot it. It may still be early though. They aren't even posting pricing yet on the gun, and they don't list the barrel/upper either. I did contact Bushmaster, and they definitely do plan to offer it in a barrel/upper. They expect that will be a much bigger market than full guns.