If you are wanting it for a survival gun it would be great. The ammo is light, inexpensive, and available everywhere. It is easy to pack, and very light.
If it is going to be a gun for the kids I recommend buying seperate firearms unless they are familiar with shooting. Lets say a cricket and a NEF single shot 410. The M6 has some kick in 410 as it only weighs four pounds.
The one I saw had a trigger bar and not an actual trigger. It didn't seem conducive with teach good trigger pull/marksmenship. Just MHO...