As fas as I can tell the Nitrated BCG that I have is holding up well , as is the NIB coated one , but I do like the Chrome ones as well . Thing is , Hard Chrome has been used in AR BCG's ( & Barrel Lining ) for a very long time & I have one thats still in service , a Phosphate Bolt & Carrier with Hard Chrome lining for the Bolt , that I built in the late Seventies , so these other new finishes have a lot to prove.
I was skeptical , at first, about the Nitrated Barrels , but they are easy to clean & even the less expensive one I have , seems to shoot good . Maybe even easier to clean then a Chrome lined . Time will tell .