Remember that extra point is restoring the heat that the aluminum takes away. You're not getting more bang for it - just getting back to where an identical head made of iron would be.
Aluminum vs iron always always always comes down to value - meaning cost vs reward. If someone places a higher value on initial buy in cost than some of the benifts aluminum will never make sense. Personally, if better heads are needed, no way I'm paying to run iron.
