We just got back from AusLUG and got a nice email from one of our customers reporting a 50% reduction in backup times. All they did is install Defrag.NSF and run with the default settings.
It's also pleasing to get yet more confirmation of the benefits our soluton offers. And yes, it was a Virtual Server connected to an iSCSI Enterprise class SAN (more on that later)
For more information on Defrag.NSF go here