Newish Mac user here. The "feel" of mouse cursor movement is one of the few areas were Windows is superior. Years ago something like this was a big issue in Linux/X.org aswell but recently it has been fixed, atleast it feels like it for me.

I have noticed this "lag" with my magic mouse. Until now I have assumed there is something wrong with the hardware in it. Or that the bluetooth connection was breaking up. When I use the build in trackpad I have never noticed any lag.

Since Apple normally pay attention to details like this, im suprised that they have ignored this issue for so long.

If you use it for a while you might become blind to it?