For me, it's multi-monitor resolution scaling. OSX sets the gold standard for that.
I still prefer using Ubuntu for my dev environment, tho.
This might sound silly, but for me it's Network Link Conditioner for simulating different network conditions. The Linux equivalents are much harder to use.
Out of genuine curiosity, what are the ways it is superior?
Either you're trying to start an argument that I want no part of, or you're asking the wrong person. I don't have much experience with any linux desktops (I've just done server stuff mostly), so I have no idea. Hence why I'm asking.