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.
It's much lighter than compared to my logitech but so is the price. Aftera while, starts getting used to it. Function wise may not be as good as my logitech or HP 5 button mouse but it's good enough. Will recommend to buy it for this price.