Amazon calculates a product’s star ratings using a machine learned model instead of a raw data average. The machine learned model takes into account factors including: the age of a review, helpfulness votes by customers and whether the reviews are from verified purchases.
I bought these to wear with a linen suit at specific warm weather event. I had so many compliments that I'll try the same trick again and again. Great quality and fit. I had read other reviewers complaining that Amazon doesn't always sell authentic Birkenstocks but I wouldn't know. If these are fakes, they're good enough for me. I compared them to the quality of my wife's Birkies (which cost 3x as much from a Birkenstock retail store) and I cannot see any difference at all. A great buy and I will add more to my collection.