Having gained a little bit of experience with electronics, I must say that making things work may be frustrating sometimes. Not this time.
I just got my Roboteq AX3500 (the open board version). It has 2 60A channels for DC motors, 8 pwm outputs, several types of inputs (analog, rs232, RC RF receiver) and accepts either optical encoders or pots for closed loop control.
I haven't fully tested it yet, but in less than 15 minutes, I've connected power to the controller (using a car battery), connected my magmotor DC motor to it, and the serial cable to my computer; installed their application and using a USB joystick there I was turning my motor back and forth just like a kid playing with a new toy.
The PC app that comes with it is very complete, nice and easy to use. The controller parameters are very complete, for example, in open loop mode (I think the same goes for closed loop), you can setup if you want regular input, exponential or log input. When you are playing with the joystick, you can monitor voltage, encoder, amps, everything on nice real time charts. The documentation is very complete and full of illustrations.
So far I'm very happy with my purchase, I'll let you guys know when I implement it into Yaboo (the name of my second robot).
Cheers
Padu