I've been a fan of CCC since I first used it 6+ years ago. Over that period of time, I think I've had one problem and Mike was quite responsive when I let him know about it. I was surprised to see a number of negative reviews here. Personally, I consider it to be one of the most useful programs in my toolbox, shareware or otherwise. I've never tried SuperDuper, so I can't compare. There has never been a reason for me to look beyond CCC because it gets the job done.