Just saw this on Yonex's site. It looks like there are only a few minimal differences from the previous Aerus 3's. Aerus X is the lower-end model of the Aerus Z. Outsole of the Aerus Z aren't normal colored rubber and comes with blue or light green colored ones. Aerus Z colorway for men is mint blue and light yellow (https://www.yonex.com/badminton/shoes/power-cushion-aerus-z-men-s) Aerus Z colorway for women is also mint blue and pastel pink (https://www.yonex.com/badminton/shoes/power-cushion-aerus-z-women-s) Aerus X colorway has the same colorways of both Aerus Z for women and men (https://www.yonex.com/badminton/shoes/power-cushion-aerus-z-unisex) Also 65 Z 2 Mens/Womens and 65 Z 2 Wide got new colorways made this year!