Product review (4 stars): Quieter front loader machines
We are pleased with the decrease in vibration of our front load washer after installation of the pads; our machine was not moving, but did vibrate enough during rinse cycles that it could be felt in much of the house.  The vibration is much less now.
We visited my wife's brother and family in Arizona in March.  Their large front load washer was actually moving on the floor due to the vibration.  We ordered and installed a set of the pads under this machine; they are very happy with the difference (still vibrates, but stays in place).