From the FAQ:

'No, CCC is no longer donationware. In order to grow our support and development team, we have made the transition to a commercial product. This will allow us to to continue offering frequent updates to our software, including new features. This will also enable our stellar customer support to remain that way. Transitioning from donationware to a commercial offering underscores our commitment to deliver the best Mac OS X cloning and backup utility on the market.'

http://help.bombich.com/kb/overview/ccc-license-registration...

From the release history:

'If you have not "donated" to Bombich Software in the past, this version of CCC will impose a 30-day trial. In order to grow our support and development team, we have made the transition to a commercial product. This will allow us to to continue offering frequent updates to our software, including new features. This will also enable our stellar customer support to remain that way. Transitioning from donationware to a commercial offering underscores our commitment to deliver the best Mac OS X cloning and backup utility on the market. […]'

http://help.bombich.com/kb/overview/release-history

You know, all of these are just glorified shells on top of the command-line tool, dd.

You could just learn dd and save yourself some money.

dd isn't for everybody. I had for example no idea how I could get features such as scheduling and archiving of backups with dd.

Sure, if you know're a shell, dd etc. guy, CCC might not be for you.