I'd take an M-16A2 in that situation. Mine worked fine in Afghanistan (and yes, I did use it), and it works fine here in Iowa in the winter. In fact, I haven't had a malfunction that wasn't due to bad mags in mine--and I've been using one with blanks and live ammo for seven years.
AR/M-16 threads are getting to be just troll chow. And those of us who have operational experience usually get ignored. Love it or hate it, my M-16A2/M203 worked fine when I needed it. So did those of the men in my squad.
Don't want one, don't get one. Just don't try to talk me out of mine.