Rustoleum vs. POR 15 vs. others

I've always used duponts metal-prep and then two good coats of duponts self-etching primer. I like to use the por-15 after that. Seems to stick very well. Depending the area but floor pans and under carriage I even like to hit it with spray in bedliner for maximum durability. Just my opinion. I hope it helps in your project.