An office document format is basically source code.
That's why the openness of a graphic format doesn't matter, but clear specifications on how to interpret an office document make an enormous difference.
I would seriously fork money over if MS would ever build Linux version.
I have never lost a document in LibreOffice, Vim/gvim, AbiWord, WordPerfect (long time ago), or OOO.
I lost a ton of documents, sometimes to the cost of many thousands of dollars, in Word. (Disclaimer: haven't used word since like 2010 or so)
People get burned, and thus jaded, by lots of different, sometimes opposing or contradictory, experiences.
As a lawyer, I deal with other people's Word products all day every day. What Word features am I missing out on? I am genuinely curious and not trying to be snarky in any way.
All those pesky macros that would allow your computer to be infected