I can't figure out how to link to the Daring Fireball post that sent me to rentzsch.com: Hole in the Umbrella: Backup 3 but it was a good one.
Wow. This is bad.
Rentzsch suggests using Retrospect. Uhhh, no. Retrospect was acquired by EMC, a mega-corp with zero interest in the home market and even worse support than Dantz (which is saying a lot). It was a creaky and ailing software package before EMC bought it, it's now a zombie. [I use an old version of Retrospect Pro for Windows, I'll use it as long as it works.]
There are some small distribution backup solutions for OS X, but they're hardly home user friendly.
Backup is in bad shape under Windows, but it's in even worse shape in OS X.