I'm a huge linux fan and run both Ubuntu and Arch Linux on a daily basis, but I used to be on OSX and Apple hardware between something like 2012 -> 2015 before switching back to Ubuntu/Arch. The only thing Apple does better is touchpad input.
And I also cannot put the difference into words, but if you have Ubuntu (even with synaptics drivers) and MacBook side by side, there is a noticeable difference in how they behave and feel but even by having them side-by-side, I can't consciously tell the difference, even if I feel it.
One of the main differences is that MacOS has visibly lower latency when scrolling / moving the mouse pointer. This is immediately visible when you scroll the same webpage on Safari/Mac vs Firefox or Chrome on Linux.
I don't know exactly why this is happening, and there is no in-browser option that can overcome this difference, e.g. disabling smooth scrolling and enabling XInput2 helps but does not overcome the difference. It seems to be something more fundamental in how the drivers work and deliver input to the user interface.
Interesting, just tried this, where I compared my laptop (Ubuntu) and desktop (Arch) with my Macbook, and the latency actually seems lower on Linux than OSX, seems OSX has some smoothing that seems to make things look/feel slower. Scrolling is clearly faster on my laptop and desktop than the Macbook (didn't even had to record a video to see the difference), tried Firefox on both Linuxes and Safari/Chrome/Firefox on Macbook with the same result.
And I also cannot put the difference into words, but if you have Ubuntu (even with synaptics drivers) and MacBook side by side, there is a noticeable difference in how they behave and feel but even by having them side-by-side, I can't consciously tell the difference, even if I feel it.