Flexy rack threaded rod material

It seems that brass is the universally accepted "best" material for the threaded rods of a flexy rack, but has anyone actually compared brass rod to any other material in a flexy rack in the same room and in the same system? I'm having a little problem shelling out 3x the money for something that is supposed to be better even though no scientific proof exists (or maybe it does, I just haven't found it).