DMG - SuperDuper! vs Apple Disk Utility.
 

Has anyone done a benchmark to see which is faster in creating a DMG?

Since DU typically does a device-specific copy, and generates a DMG that can only be restored to a system with similar geometry, it can do a block copy and will be faster in many cases.

However, if you've got a read/write image, and you use Smart Update after the first time, SuperDuper! will be much faster the 2nd time around.

As long as the image is read/write, killinghall, yes.