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.
This is sadly one of the cheaper ones (even though it costs quite a bit) with only a single mode ("clean") with 2 different intensities. Comes with RFID feature though, easy-start, timers, pressure sensor, extremely good battery and the "smart" brush replacement notificator.
Overall it looks really good, is quiet. I'm happy with my purchase