The controller has been used with some very heavy robots. See the one with the tank tracks that shows up in the home page picture rotation.
The challenge is the amount of amps, which in this case is tightly related to how much geared down your motor is.
Consider simulating your robot with the Electric Drive Train simulator at
www.enigmaindustries.com/EDTSim.htm
This will help you determine the power your robot is likely to draw.