I sandblasted my frame and used Eastwoods Epoxy Primer and it works fabulously. Very tough stuff. I sanded and topcoated it with Chassis Black. It looks great, but I don't think the Chassis Black is as tough as POR15, but it is easy to sand a chip or scratch and spray on a little more.
I have used POR15 and their Hardnose Paint with luck. I am never able to apply a second coat of POR15 within the 3-4 hour window they require (family, kids, work, the beach, etc), so I always have a quart of their Etch Primer around so I don't have to worry about the re-application window.
The Hardnose paint is exactly what they say, hard! But application, whether by brush or spraying, doesn't provide a perfect glossy finish. So use it in places that get covered up. I did the inside of my fenders, under the hood, firewall and inner fender skirts. I brushed the fenders, and under cab, but sprayed the firewall and under hood so it looked nice. It has a little orange peel texture, but since it is bright yellow it looks pretty darn good.