After another interaction with Benjamin, I can tell you he really cares about his users. I bought a new computer and again ran into licensing trouble but Benjamin had me sorted out within 12 hours.

MimMac also handles packages well (iPhoto, Aperture generate packages into the hundreds of Gigabytes), treating them as folders so you only have to update the files which have changed not the whole database (minutes instead of days of copying).

MimMac is the only affordable high quality sync tool available on OS X. SuperDuper! is the way to go for volume backup but SuperDuper! doesn't handle folders or partial drives well and won't do two way syncing at all.

MimMac and SuperDuper! are a killer combination though.

I've since bought another license to support the developer's efforts with MimMac, despite our rocky start.

What's even better is the licensing scheme will be changed so that your license will continue to work even if Ascendent Softworks disappears (hopefully not!).

All that's left on my wishlist for MimMac is dry run preview of two-way syncing.