Product review (5 stars): Links to important Consumer Reports information, and analysis of 5 star vs 1 star Amazon ratings
The following also appears as a Comment after the reviews by "J. Littrell" (most helpful favorable review on 24 July '11) and "Timothy M. Watson 'TimW' " (most helpful critical review on same date).

Full links to important Consumer Reports (CR) video information appears in those Comments. Here, because Amazon apparently does not allow links to appear in reviews, I indicate how the CR video Links to can be accessed by way of google search:

Per information on Consumer Reports, the first guard against vibration is the purchase of a washing machine that has built in vibrational dampening that is effective.

[ Video Link deleted by Amazon. Google: " laundry--cleaning/stopping-vibrating ", and go to first hit, from Consumer Reports, and see the video, etc. ]

It is likely that the many 4-5 star reviews versus the set of 1 star reviews here at Amazon indicate that the Silent Feet product works reasonably well with many models, across a range of lessor vibration issues -- but cannot effectively mitigate vibration in the cases of the worst designed machines. (If some of the Amazon reviews are accurate, the product may indeed worsen the effect in some unfortunate cases.)

This "works for some, not for others" is a reasonable, technically grounded explanation of the data, and also explains why Consumer Reports (CR) data does not align with Amazon reviewer experience.

Amazon reviewers are testing a range of different machines with different degrees of vibration, while CR apparently only tested the single worst vibrating washing machine in its test of Silent Feet and related products.

[ Video Link deleted by Amazon. Google: " Inside Consumer Reports Test Labs: Reviewing antivibration pads ", and go to first hit, from Consumer Reports, and see the video, etc. ]

Kudos/cheers to Vibration Solutions LLC (producer of the Silent Feet product) for offering refunds in the cases where their products are not effective.

I would be a more solid fan if they also offered full web links to all of the CR information on their tests (and not just the positive seeming), and if they would perform their own accelerometer tests, like CR, on a series of at least 3-5 washers with unbalanced loads, on a mock standard subfloor-and-joist station (worst case, like a 2nd floor condo installation) .

That is, for highest consumer regard, Vibration Solution LLC (Silent Feet mfr.) needs to offer their own study and analysis (indicating the models for which their products don't work), or at very least fully report the CR analysis available, even though seemingly negative, along with explanation of the sort I offer here.

Prof D, product owner