I don't own one, but I have lots of experience with two through the HRA. In the past shooting sports fairs, I've seen them eat up just about any .22 lr ammo and run, and run, and run. All with pretty much no maintenance. They really are enjoyble guns to shoot. If anything, they are on the heavy side, so that can be a little bit of an issue for younger shooters, but not a problem for adults.
They seemed to be quite popular with the younger shooters who were familiar with the MP5 from video games. I was always amazed that these 10-13 year olds were able to pick up the gun and knew all the controls. I'd ask the parent if they had shot the gun before and they said no, they learned to do it from playing Call of Duty or whatever other games that have those guns.