When I said in the other tread that I was too paranoid to use aluminum, I was only talking about friction savers.
They do take a beating when being pulled out of trees by someone too lazy to use a throwline to lower them with ( that would be me!)
Aluminum gets dinged up too easily when it lands on concrete or asphalt.
Except for that I'm with the majority here: steel for rigging aluminum for climbing.
With one exception: when fastening the end of a SRT line around a tree, I always use a steel carabiner. That way, if I have a bad day and get it set so it can roll up the treetrunk and put the load on the gate, it'll still hold me.
Paranoia again, probably.