The backup landscape has changed. An M1 Mac requires its internal drive to be in working order otherwise it can’t run. This removes the main reason to have a bootable backup. A bootable backup used to allow you to get back in business quickly after an internal drive failure, but not any more.
If the Pre-Boot container is damaged, the Mac is unable to boot, even though it may be connected to a bootable external disk, as the only Pre-Boot it can use in the early part of the boot process is that located on the internal SSD.
The Mac has moved quite a bit closer to the way an iPhone or iPad works with the arrival of the M1 family of chips.
Limitations around the start-up process and and restrictions on installing low-level extensions to the operating system give Apple more control over their operating system and, arguably, give users a more secure platform.
For reasons lost in the depth of time I have licenses for both ChronoSync and SuperDuper. I have not used Carbon Copy Cloner.
So this will not exactly be an answer to your question.
Currently I use both. ChronoSync to make daily copies of my images drives (one hobby is photography), and SuperDuper to make a daily backup of my startup drive. And as of a recent update SuperDuper can make bootable backups (as does ChronoSync).
But as Karl has pointed out, bootable backups are not as useful as they once were. They can be of use when upgrading the OS, should things go wrong, or if you have the occasional need to run an older version of the OS. I have not booted from such a backup in quite some time.
Both have been reliable set and forget utilities that I’ve used for some time.
Thus I guess the question you’ll need to answer is what is the reason you want/need a bootable backup. And as both ChronoSync and SuperDuper offer free trials, give them both a try and see if they meet that need.
Thanks!
The damaged Pre-Boot container making the Mac unable to boot is what convinces me to abandon wanting a bootable copy.
Currently, such a copy would have little utility.
In the past, using intel based Macs I appreciated the security of booting from an external drive in the case the internal drive were to fail.
And during the past ~10 years and 2 different iMacs I never had an internal drive failure.
(…just because you’re paranoid doesn’t mean that aren’t out to get you. )
Between the reliability of SSDs and Apple’s changes to the boot processes I find bootable external drives less useful. Main need is to recover quickly from something that hosed the current install. Current recovery plan is to use MacOS recovery to get OS back then CCC to put everything else back.
Both are basically user-friendly front-ends to rsync or the idea of rsync, the command line program which is already part of macOS.
Both are just fine and you can’t go wrong with either, IMHO.
Chronosync is a one-time purchase (with all future upgrades for free) where as I suspect CCC will expect payments for future upgrades (at some point).
Chronsync probably has more knobs to turn to provide more finely controlled syncs. I find scheduling features pretty much the same. I find CCC more reliably mounts un-mounted source/targets, but that may just be me.
I use both (along with rsync). With inflation and perhaps in future having to relinquish a license fee, I’ll probably stick with Chronosync and rsync only.