Jeff.... I for one had no problems with upgrading to the MaxStepper. Basicly I built the kit and put it in line between the computer and the parallel port of my controller. I had to invert the Z in the table setup and that was it as far as software was concerned. I had to disconnect the Home and Limit switches from my controller and connect them to the MaxStepper.
Now I had to do some tweaking with my feed speeds because the Max ran so smooth and fast. 10ipm with parallel to 120ipm with the Max.
I also had to recalculate my time for making coffee inbetween setups..... that time was cut by 12... ;-)
Upgrading to the MaxStepper was the best thing I had done for my machine.