mines duty coated. it holds up fine. Its not a metal treatment its a ceramic surface treatment. Mine has one spot of wear on the under side of the slide where the twist of the gun causes it to rub. Underneath its stainless.
It actually isnt black either. mine is a blueish has a rainbowish flecks in the finish when sunlight hits it. dont really know how to describe it. its not black for sure. A nice coat of oil makes it look really black and sexy.
Armory coat is that deep flat black paint like finish. more the look you'd like I think