Look very closely at the valve seat areas, I have seen 4 heads sold by a friend that is a machinist, drop the seats right out of them, both intake and exhaust. No, the heads weren't ported or modified, they were right out of the box new and all 4 heads went less than a thousand miles before disaster hit.
And, the other areas mentioned in this topic as well.
Pro-Comp seems to be a company just bent on knocking off other's parts, for profit only. That is just what they appear to be. I agree, the bitterness of poor quality long remains after the sweetness of cheap price is forgotten. The main issue(s) with Pro-Comp seem to be that they exude that their parts are the greatest thing since holes in donuts, when they clearly aren't.