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.
Was keen on a shampoo bar, but didn't realise that this is also designed to be used as an all-body soap bar, too! Have been using every day for two weeks now, and it's true - it maintains its shape and doesn't seem to shrink as much as other brands. I literally only use this + some face scrub in the shower now. Great product, good value, would recommend.