SuperDuper is the only backup utility on the Mac that preserves ALL filesystem metadata. CCC and all the rest have problems with something or other. See this: http://blog.plasticsfuture.org/2006/04/23/mac-backup-software-harmful/
Personally I prefer SuperDuper! for it's ability to do backups only copying the changed files. And lots of people are reporting that it works well enough on Leopard: the incompatibilities appear to only be in slightly unusual cases.
SuperDuper! But what's the deal with it not being Leopard compatible yet?? It's driving me nuts.
Yeah, the problem is that you can't boot from the external - at least that's what I've noticed...
That's not likely to be a problem with SuperDuper!, rather a problem with the external drive. Not all bridge chipsets are bootable. For example I have a number of Firewire externals, all of which are bootable when SuperDuper! makes a bootable clone. I also have a single cheap USB enclosure: this is not bootable.