I prefer rattle can because they WILL get scratched. Powder Coat is a PITA to touch up (Must sand the area completely, then use a rattle can ) or you must burn it all off, then blast and re-powder coat, which is what
@dogfishlake is doing.
Personally, blast it to a near-white surface (SSPC-SP10, then immediately spray bomb coat it with a HD Automotive Epoxy rattle can or industrial paint, then let it cure, do a second coat of primer, then two or three coats of top coat color (gloss black, flat black, hot fuschia or color choice). This way when it does get scratched, you can do a light sand and clean-up, re-spray, and you're done.
I deal a lot with industrial equipment and the BEST coatings are for marine-based areas. These are very expensive coatings, are very durable, and can last a very long time. However, ANY coating can be scratched and if it does, there is a PROPER repair procedure.
In the perfect world, I would do:
Near white blast sandblast.
Zinc Clad II Ethyl Silicate inorganic zinc rich primer
Macropoxy 646 (Yes....) polyamide epoxy
Acrolon 218HS Acrylic Polyurethane in whatever color I want.
This would be a highly durable finish, would be reasonably impact-resistant, but would cost probably $1000 to do just because of the cost of products. It would also prevent rust for a long time, unless someone scratched it hard and did not repair it.
So, I'll use spray bomb epoxy, and rattle can gloss black for mine........