Being a steel type specialist, (My team consisting of Empoleon, Steelix, Lucario, Scizor, Bronzong, and Magnezone) I am slightly biased in this argument, so of course I voted for Scizor. But even before I liked steel types, I always thought Scizor was just the boss, and it is obviously more useful in battle, being the king of OU in gen 4. In a battle, Scizor would whoop Scyther easily, with all of Scyther's STAB moves bouncing harmlessly off Scizor. But I have always liked Scyther, too. Both Mantis' are epic in their own way.