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.
We went from store-brand cat food to Hill's Science. My cats love the dry food, and it's supposedly much healthier for them than the alternative. While a little on the expensive side, it does seem to last us quite a while.