Not that easy to compare with others unless using similair components.?
For instance your using Analog drives which don't compare to Digital drives. Then your using less than 50v and most like Neil who have paid attention will be using 60v+ with digital drives.
Then we throw into the mix external Motion control which makes huge difference in performance over parallel port or low spec cards. Together all these things can make night and day difference in performance for machine using same motors/weight setup.

With your setup I wouldn't expect much above 8000mm/min and still be reliable.