I think Rustoleum works great on frames. The paint is more durable than most give it credit for once fully cured. Doesn't like prolonged contact with fuel, but on a frame it wont see much fuel if any.
I media blasted my frame, primed with epoxy and top coated with Rustoleum (used my HVLP spray gun). The other thing I like is that touch-up is easy if I scratch it or have to drill holes, bang on it to straighten, etc.
You can have a UV protectant added to rustoleum, and I suppose also use a hardner too. Its one of those things of any paint is better than no paint, and rusto is likely way better that what the factory did or didn't use on the frame and associated parts.
