I use several different brands of paints, depends on what I am painting the the paint scheme. For the Southern 4-6-2 I'm doing now, I use Scalecoat II.
For finish coats, either gloss or dull, I use Testors which is a lacquer based finish.
It doesn't matter if I paint plastic or metal. I always spray a coat of primer on the model before spraying any colors.
Sitka, nice job. Although I don't use the rattle can paints, I do know that they can produce a nice finish. Keep up the good work.