Today's best "paint" type gun coating is Cerakote.
It's good enough that some guns are now Cerakoted by the factory.
Custom gunsmiths are using it as a coating option for people who don't want hard chrome or bluing.
Cerakote says that their ceramic-epoxy based coating is tougher and more durable then bluing or parkerizing.
With any of the coatings prep and application are critical.
As example Cerakote's process is very exacting about what bead blast media needs to be used, how the metal has to be degreased, and how the coating needs to be applied.
Lauer Duracoat and Cerakote as well as others can match the FDE color, since that's a US specification color and they make the paint to that specification.
For an idea of how Cerakote needs to be processed, they have a tutorial on their site:
https://www.cerakoteguncoatings.com...=01 Brand&utm_term=cerakote&utm_content=Brand
This is a high standard, but any of the gun coatings can only work well if treated the same way.
Where all the coatings can fail is when the applicator tries to do a rush job with improper equipment and fails to get the bead blasting and degreasing right.
Done wrong, the coating looks bad and fails to adhere or wear well.