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 an okay product. I feel I could achieve the same or better results with a non-electric set. Also, the filer attachment is not impressive. They do provide you a set of extra attachments, which is good.