Product review (5 stars): These work well
When our front-loading washer and dryer were in the garage (concrete floor), my wife and I never noticed nor particularly cared whether they moved. Spinning was also not a concern, although the noise would sometimes let us know when the laundry was almost finished.

Things changed after moving to a house with a laundry area. Suddenly the spinning became noticeable. Sometimes it seemed to shake the entire floor. Tile on a raised foundation can do that. I tried jamming cloths between frames, leveling the pedestals, and showing how to load the washer more evenly, but none of these stopped the problem.

So I looked for some type of anti-vibration pads and these came up in a search. They have generally positive reviews, so I decided to test them out even thought they are somewhat pricey. I am happy to say they work as advertised. The laundry area is much quieter and the washer and dryer stay put.

Installing them is a two-person job. One person tilts the machine backward, the other person puts a spacer (2x4 works well) under the front feet. Next, one person tilts the machine forward and the other person slides the rear feet into place. It only takes a few minutes for each machine. These pads are well worth the time and cost.