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.
Fantastic piece of kit. I previously had a more basic model of Philips razor which did the job for years, but upgrading to this has been well worth it. Incredibly fast, smooth and close shave. Nice hard shell travel case too. Recommend spending the extra vs cheaper models.