teflon slip easier on the clutch bell and dont grab as well and they dont need any maintaince. Aluminum grabs good but need to be maintained once in a while, they mushroom over on the edges and needs to be saned down. For easier no maintaince go teflon, if you want good grab get the aluminum.

Maintaince is part of the hobby and i dont mind doing it so sanding down shoes once in a while is no big deal. I personally have never seen a steel clutch bell worn down by an aluminum clutch shoe.