Have one, but it doesn’t live a hard life. If I ever have a blued rifle refinished again, it’ll get nitrided. Have a couple with factory nitride and really like the look. Supposed to be really tough and rust resistant too.
I have one Cerakoted gun, which lives kind of a soft life for obvious reasons:
Black Nitride treatment I had done by H&M Metal Processing of Akron OH on guns which don’t get babied: