which works best CCC or super duper?

Yes.

I own and use BOTH SuperDuper and Carbon Copy Cloner.

Both have saved me from failing boot disks.

CCC has more flexibility, and the ability to perform network copies (very handy).

SuperDuper just does clones, but it does it well.

SuperDuper will do a full from scratch clone for free, so it is useful for that user that needs a one-off backup but does not want to pay for SuperDuper or any other backup software. Incremental updates to an existing clone and scheduled backups requires paying for SuperDuper.

Carbon Copy Cloner has a demo period where all features are available to play with. Useful for try-before-you-buy, and for that once in a lifetime need to get a backup. After the demo period you have to either buy or stop using CCC.

So I have SuperDuper updating a clone every day to a local attached hard disk.

I have Carbon Copy Cloner running on an older Mac that uses the network to backup laptops in my home to a NAS (it is very Rube Goldberg; but it works).

Carbon Copy Cloner is also good for just copying sets of folders and can include or exclude specific files in the copy. CCC can also has a safety net so that files which are removed from the source get saved off to the side on the CCC backup, so you have a limited period of time (you get to choose how long) when you can get files back that were changed or removed.

Like other users, Carbon Copy Cloner since about High Sierra and still using on Apple Silicon M1 with Big Sur and Monterey.

Notation specific to Monterey Bootable Clones where be it Intel or Apple Silicon - the Developer has suggested abandoning the Legacy Bootable Clone on Monterey.

Some background changes somewhere in Monterey 12.3 to 12.3 1 and again from 12.3.1 to 12.4 the ASR aspect of Monterey has changed making the Legacy Bootable Clone not viable

Making bootable disks is getting more and more difficult.

AFAICT, both programs have made excellent work of keeping up with the growing restrictions that have been imposed in recent versions of macOS.

I use SuperDuper!, and I am able to update the data part of my clone drive so as to keep the clone up to date.

The drive is bootable.

But when I update the OS, I will have to boot from the clone and update it too, instead of cloning the system part.

I suspect that with CCC it should be pretty much the same thing.

From where I stand, I think that both programs are great, and so has been the support. I use SuperDuper! because I bought years ago, and it has served me incredibly well, but all that I have read about CCC suggests that it is an excellent tool, and also it has been there for a very long time.

Another point is that I have both Intel and M1 Macs. Bootable drive works fine with my Intel and not very well with M1 and Monterey. That last system has many lockups and crashes while trying to boot from an external drive so keep that in mind down the road.

I have used CCC for several years and it is great. I cannot speak to Super Duper.

Very good point.

I don't have an M1 mac yet.