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.
Cheap! How else do you review Coke? Everyone knows what’s its about. You either want it, or you don’t. But if you do want it, I then it all comes down to price and convenience and this wins on both accounts!