Black oxide is more durable than blue. Blueing is a type of oxidation of the metal surface. Black Oxide tends to add some hardness to the surface whereas blueing does not.
However, bluing is usually more attractive than black oxide and usually shinier. Black Oxide is usually flat black.
Nitride coating (melonite/tenifer/armonite) is the best IHMO.
Rosewood
I thought they were two different processes. There are different kits to do the work available on Brownells. Some called blueing, some called Black Oxide.black oxide is blueing.
surface underneath the black oxide determine the sheen of it, if polished, you will get a deep shiny blue, if bead blasted, you will get a matter appearance.