I'm going Rustoleum. But I'm in sunny Southern California and my truck has little or no rust on the frame.
If I were you living in the "frozen North? I think I'd default to the more protective paint assuming you can afford it. Just my $.02
Dan brings up an excellent point. He lives in California... For those of us in climates where we don't get much rust we can get away with less durable paint products. I now live in Colorado, I use Rustoleum products for painting frame / under the truck stuff. When I lived in Ohio I always used epoxy products for these applications, sometimes then using undercoat over that.
So geographical location is also a part of choosing what to use.
