The Hammer Strength unilateral supinated-grip pulldown is one of my favorite machines. It's nearly impossible to duplicate with free weights what this machine can do.
Several training methods work great on this machine, like maximum tension alternating pulls (hold one side isometrically in the contracted position at the bottom while the other side is moving). It also works great with bands for added accommodating resistance.
Back in my small hometown in Texas, some of the more eccentric churches would hold these great tent revivals. Even if we didn't like their particular style of religion, we would still sit out in our cars and watch just for the sheer entertainment value of the show.