Black oxide maybe fine, I dont know. Should be. I like brush stainless because you can maintain the finish for a lifetime or two. I am not sure there is any advantage to oxide stainless over a comparable finish on steel. A stainless barrel might last longer and the blue steel might machine better for a given amount of effort. I say might, kinda forget. Maybe some advantage to a small shop keeping with one material.
It is not just a question of durable, but how does it look with the inevitable dings and wear. Sorry, again, I dont know. Blue steel ages gracefully and stainless is perpetual.
Sorry no help, consider this a bump. Conversation stimulator?