Product review (5 stars): Anti-walk Silent feet work
We purchased a front-loading washer and installed it on the first floor in the laundry area.  When we purchased this machine, I knew it was known to cause vibrations and shake floors when it spun the clothes, but it was very well rated.  So I reinforced the floor under the machine.  Even so, we still had very noticeable vibrations when the washer started to spin.  The shaking could be felt on the first floor and the second floor of the house.

After installing the anti-walking/vibration feet, there was a 90-95% improvement.  The machine still shakes, but there is only a very small amount of vibration to the house. It's almost imperceptible.  I hope these feet can stand up to years of stress.  It's worth buying this product and giving it a try.