SuperDuper!
Used by 24 peopleshirt-pocket.com ↗

“To continue the backup story, I'm a SuperDuper! guy to clone drives nightly.”
Geof Morris Interview, Aerospace and systems engineer · via Uses This 
“SuperDuper! is a critical part of my software setup.”
Rich Siegel Interview, Developer and co-founder, Bare Bones Software · via Uses This 
“Backup is handled by cloning my drive with Superduper.”
Tom Armitage Interview, Game designer, technologist (Hide and Seek) · via Uses This 
“And I use SuperDuper for backing stuff up but who cares.”
Joshua Allen Interview, Funny writer dude · via Uses This 
“I have recurring, automated backups on a couple external drives through SuperDuper.”
Frank Chimero Interview, Designer, illustrator, writer · via Uses This 

“I make a bootable backup of the first drive onto the third drive using SuperDuper! every few weeks.”
John Siracusa Interview, Programmer, writer (Ars Technica) · via Uses This 
“Every night I use SuperDuper to clone my MacBook Pro's internal drive to one of the two aforementioned Lacie hard drives.”
John Gruber Interview, Writer (Daring Fireball) · via Uses This