My tactic is to kill a dark aeon. If it doesnt drop ribbon, just reset and kill it again till it does. Although they do give the armour with other wasted abilities as well as ribbon.
Kill dark yojimbo four times then leave the cavern and come back to kill him another four times. You rack up some nice equipment and get to keep it all.
Originally Posted by Wolf Kanno
Ivalice is not simply a place in a game. It is a real world, it lives and breathes