How can I sync backup hard drives?

Episode 1146 (30:13)

Bob from DeMoines, IA
LaCie Little Big Disk

Bob got a new MacBook Pro and he's using a 1TB Little Big Disk drive for backup. He wants to use a second drive for redundancy. How can he sync them both? Leo says that SuperDuper! is great for that function. It'll clone it and then make it bootable. ChronoSync is good for backing up as well. But Leo thinks Super Duper is the best option.