How many people have problems with the heads breaking ? Seems to me that if they don't crack when dropped on a tile floor, or have the threads strip when overtightened, and get warm when dipped in hot water -then it makes little difference what it's made of. Except maybe to a replating company.
A few posts above yours is a gentleman who dropped the head of his R89, and seeks a replacement. He's not the first, a quick Google search suggests.