I like my little cloner/wiper because it gets them off my workstations and can handle it all completely disconnected from a computer. Its also handy when logical recoveries come in because it can clone a healthy drive at speeds up to 6GB/min. I'm actually considering buying a couple more of them.
But even with just one, I can wipe 6~8 good size drives per workday. Though I usually just plug in two each afternoon before I go home for the night, and the next day they are ready. It also keeps track if it finds any bad sectors on the drives, so you know if they are failing before it happens during cloning an actual job (very annoying when it happens).