These guns are a lot like the Sten gun in principle, not so much application, as they
are a very cheap to produce firearm based on a tubular receiver.
The plethora of aftermarket junk magazines is the bane of their existence and the cause of much of their bad reputation.
Operator error, I say is 95% of the issue...if you take care of your gear your gear will take care of you.
Take the one, for instance, featured herein, as once the feed ramp was polished it has never had a misfeed...goes bang 100% of the time.
The barrel extension however throws the point of impact off enough that I prefer to fire it with out it on....but it does look cool, doesn't it?
And I did buy the aftermarket magazines so I had some spares but they are so far off in dimension they are only junk cluttering up my gun safe now.