How about Differential with SuperDuper!

[randyharris]

One feature that I love with Aconis True Image on the other platform, is that if you image a drive to a file, you can then do differential images using the original full image as the base.

Any thought to giving SD! this functionality when imaging to a sparseimage?

I like this feature because of the risk you run updating your backup image too often, you may be backing up a problem from your main drive, then the backup becomes worthless. Being able to differentially backup to a seperate file reduces this issue considerably.

Please consider it, it's a neat feature.