Friend of mine has a couple, one semi-auto and one select fire with a silencer. The select fire is a blast to play with. Not really sure if it has any actually USE in the civilian world, but it sure can eat up a thousand rounds quick. I don't think he's experienced a lot of problems with it. I know when I fired it, it never missed a beat.
I'm not really into that sort of firearm. I don't really see a reason to own any .45 or 9mm carbine of any kind. I like lever guns in magnum calibers, but auto pistol calibers are for auto pistols IMHO. I really have no use for 'em in a long gun. You may retort the Cobray is a "pistol". Well, it's not exactly holsterable, is it?