I dont know if im experienced enough with body work to comment. BUT, i have never used anything but krylon flat black industrial primer, i have doneall my own body work(with hammers and anvils mid you i HATE bondo) and i have also done all my friends ricers. I consider myself good but not an expert. I have apways had professional and long lasting results with rattle can krylon. And i am currently doing my z flat black with krylon industrial.
i dunno if this will help you. but this is just my experience.