I wished that when it is unnotched, scrolling would behave like scrolling on a trackpad. It still jumps lines, instead of smoothly moving. The sideway scrolling is awful. No idea how far to scroll before something starts to move.

The mouse is definitely nice to hold, but trackpads still provide a much better scrolling experience. Excel with large row-height is near impossible to navigate without a touch pad in my opinion (and whoever at Microsoft thought it was a good idea to only be able to scroll in whole cells should never work in usability again)

The 3S is supposed to have more quiet clicks, which I consider another improvement.