I have the Dong San Spas shotgun (Dong San was reborn as KT).
It's mostly plastic, but still a good quality gun.
One of the things I like is that my Spas will take AEG springs. The internals are beefy enough to handle up to an M120.
All of the cocking components of my Spas are metal and the ABS plastic is fairly thick and sturdy.
Now, I can not speak for the lever action, but if the quality of my Spas is any indication, it should be a worthy investment.
The only reason I haven't bought one is because I refuse to spend that much money on a springer.