All OSs have their issues. I use Windows and Ubuntu daily and have had work macbooks.
In a lot of cases it does come down to what you are used to, as there are design differences that aren't necessarily worse or better but when you get used to one the other feels janky.
At any rate, in Ubuntu's case things like display support are worse - especially multiple different DPI screens (yes, there are workarounds). UI is less slick in places. Some software is better supported while some have worse support. Things like that.