Chronosync is one of the few 5-star apps that I use right up there with 1Password and Keyboard Maestro. I originally purchased Chronosync 3.3.5 back in 2007 for $30. It's amazing that my license is still good today and this app continues to be updated and supported. This is a superb backup program with tons of options and customization potential. I use it for 3 things:
1) creating a bootable clone 2) cloning my external data drive 3) syncing a documents folder between two Macs.
It handles all these tasks superbly and without issue. I've needed to contact support a only a few times over the last 10 years, and response time has been quick and professional. I highly recommend this app for your backup needs and can't imagine a backup workflow that could not be accomplished with this app.