I tried CCC several weeks ago, running in Demo mode. Worked perfectly. Although I did have a problem with part of the "Schedule tasks..." function. That solved itself with a restart of the app or computer, not sure which.
I was already using SuperDuper, but I wanted to see how CCC compared. Quite well, as a matter of... opinion!
The external drive I used for SD was partitioned and I never seemed to use the non back-up part. So I re-partitioned it with two ~1BG volumes and gave SD and CCC each one. I always turn that drive off each night (along with the iMac) because the drive doesn't seem to 'sleep' properly. Sometimes, I forget to turn it back on! That causes problems for SD because it seems to simple stop when it can't find its assigned backup volume. That seems to also stop the automatic Shutdown process, SD simply won't accept the Systems "Quit" command.
There may be a setting somewhere in its prefs that tells it to 'give up' after a reasonable amount of time, but I haven't found it. CCC, much to my delight, has a clearly available setting to 'kill' itself after not finding the assigned backup volume.
It also can send an email with that or any errors it sees. It also uses Notification Center, of course.
CCC 4 was recently released and it has some major improvements in its interface! Most of the scheduling and task creation settings are available on one window. Parts of that window is a 'side bar' that can be hidden if you need more screen real estate. And the whole window can be 'simplified' if you don't want all the details in view. All in all, I'm glad I bought the app. It seems much easier to use than SD. And offers plenty of pop-up info to explain most of its controls. Support is easy to get and often you get replies directly from Mr. Bombich. I highly recommend it whether you have SD or not.
Just remember what President Lincoln said, "You can't have too many backups!"