Flawlessly creates bootable backups. Carbon Copy Cloner occasionally freezes when backing up to firewire hard drives, and Restrospect routinely breaks aliases. This program has passed the ultimate test ... I have used it to clone the machine to multiple other Macs, as well as firewire hard drives. Once you copy over everything the first time, it's quite fast to copy only the "differences" when you need to do a backup. Five stars ... I immediately bought licenses for every Mac that I maintain.