Well 10:1 res:armor is the theory though in practice resistance comes in much larger quantities. You're not going to see much armor with 600 armor bonus.
Furthermore since barbs have naturally higher strength and armor, it's generally more beneficial to get resists, it's much easier to increase whatever is lower by w/e % then it is for whatever is bigger.
Also, I understand it's under testing, but no player pvp dmg penalty? lol