I got a NIB GSG5 out of a deal a few years ago. As it is, it's pretty horrible, but after a trigger job, smoothing out the action a bit and removing the mag disconnect, it's been a decent and surprisingly accurate plinker. Would I buy one? Probably not. It doesn't do anything a 10/22 wouldn't do much better.
IMO the best way to get a "black" .22 is a good .22 upper on a regular AR15.
IMO the best way to get a "black" .22 is a good .22 upper on a regular AR15.