The last time I used it, I was running a machine at the McCormick Center in Chicago at the Coverings Show. Somebody leaned on the E-Stop and stopped the machine. To get the SStepper running again required a complete re-boot of the computer. Nothing else would work. Not good and not ready for prime time.
I've crashed it a bunch of times if the tool change routine is interrupted. Also, it doesn't seem to like the master / slave set-up either. Finally, I have a homing routine that turns off the softlimits, homes, moves to position, and then turns the softlimits back on again. Works perfectly under Mach, but not with a SStepper.
Anyway, I've found too many flaky things to believe I can use it on a production machine - fine for a home shop though!