Meh, all the way up until the point where he shows you he can use the damn thing. I've seen a few fellows at ranges who are shaming people using considerably smaller-caliber handguns, and even if the follow-ups are a tad slower it's not like that first hit isn't going to count.
Generally speaking though, I'd be concerned about folks armed with this in battle, only because that means they've got a lot of financial support. ;)
-B

