Yeah, my stuff is all a combination of functional armor, and costume armor. The c.1300 kit you see in my avatar photo is all aluminum butted mail. It sure is comfortable at the renfaire, but wouldn't help much in a fight. Better than nothing, but certainly not durable. The helm, on the other hand, is around 16 ga, and is steel.
My plate harness is SCA "munitions" armor, and I've started adding other components to it that make it more viable, such as riveted steel voiders and fauld, GDFB sallet and legs, and when I get around to it I'll also have a mail standard (I own the mail, I just need to line it, etc).
Now I'm also working on a mid-14th C. kit, and the legs and arms are functional armor, but I don't have anything new for the torso yet (which for renfaire purposes can just be hidden with the surcoat).