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.
