POR15 is very glossy. If you want a flat or satin finish you should shoot (rattle can) it with a satin paint after painting with POR15 but before the POR15 is fully hard (if you are painting with a brush, you can start shooting the front by the time you have painted your way to the back.
I have used POR15 and ZeroRust. I like both products but they are not comparable from a hardness standpoint. POR15 is more like a hard/slightly flexible ceramic surface. ZeroRust is more like rustoleum . . . i.e. if you smack it with a hammer or brush up against it with something abrasive, it comes off pretty easy, not so with POR15.
Ken
