* The person needs to exchange forms in Word Documents with other people (agencies and public authorities) on a daily basis, and the exact formatting matters, so LibreOffice doesn't cut it.
* There is trade specific software for which there is no alternative (open source or paid), which the person couldn't replace with an alternative if there was one (because it's effectively agency mandated), and which only runs on Windows. (And to give you a sense of how special-purpose this is: it has it's own hardware VPN box which you have to put between your computer and the internet.)
So it's sad, but the requirement is not "at least as good as Windows" but "Windows".
* Legacy Intranet websites that only work in IE.
The person I'm talking about is self-employed and not, erm, technologically affine, so why not just stick with Windows?
> why not just stick with Windows?
Hm... because Windows is essentially a platform for Microsoft and assorted 3rd parties (most of which are not even affiliated with them) to spy on and meddle with you beyond any reasonable control or limitations?
Edit: Well, the edit just done to the parent comment makes my comment mostly useless now. :P At the very least, speaking to the specific example of Word documents, I’m not aware of any features that current Windows Word has that Mac Word doesn’t (that would result formatting not carrying over perfectly).
It lacks the extended functionality (i.e. in Excel: PowerQuery/Pivot/Map, Inquiry) or for some reason doesn't work (Mac Excel does not work with psqlODBC - Windows Excel does).
Windows-only software is far, far more common than Windows+Mac software.
(The software I'm talking about is Windows-only. I know you might mean Mac Office.)
PS: And because writing portable software, deploying and maintaining it is apparently hard, companies are now switching to web-based solutions. Yay :(
To non-Canonical Linux or FreeBSD/OpenBSD please.
OSX and Ubuntu spy and expose you too, although Windows is by far the biggest offender here.