Size is decieving. Pound for pound, the leopard is the second most powerful big cat in the world, being topped out only by the Jaguar. They are incredible ambush hunters and display a frightening level of cunning. Most man eating lions and tigers have no finesse. They also won't drag you up a tree while you're still screaming, a Leopard will.
As an aside, most cats are capable of taking prey significantly larger than themselves. Bobcats in particular have been known to kill prey animals that are several times their own size.