Self Etching primer... Good or Bad?

The way I've been taught is:
Bare Metal -> Epoxy Primer -> Body Filler ->Epoxy over any filler or bare metal -> Urethane 2k primer -> Sand... -> Urethane 2k primer -> Guide coat -> Sand...basically keep priming and guide coating...and sanding until you have a laser straight panel -> Sealer -> Base Coat -> Clear coat


I've found epoxy primer works well, and is tough as nails.