We posted a beta of CCC for El Capitan beta testers back in June and I'm happy to report that our testing of CCC 4.1.4 (beta) has been going well on the new OS. So far we haven't found any significant problems. We've made a couple adjustments to how the Recovery HD partition is cloned, but that change was relatively minor. Backups are bootable, scheduled tasks are running on schedule, smart updating is updating smartly, backups to network volumes are working great. On the whole, this appears to be a low-impact OS change.