Product review (5 stars): Great product for washing machines!
I live in an upstairs apartment where I installed a washer/dryer combo in our kitchen.  It vibrates quite a bit during the spin cycle and shakes the whole building.  I bought these and they stopped the shaking for the most part.  I say 'for the most part' because when the spin cycle is starting up (low rpm) the washer/dryer shakes at a lower frequency and the Anti-Vibration Pads don't help as much.  However, this is only for a few seconds, and once it is up to full speed there is no more shaking.

These are tricky to "install" by yourself, so I recommend having someone help you.  Other than that these are great, especially if you want to avoid bothering your neighbors.