Andy_Mac_Scotland Not sure. What I have to have is the ability to use comments and track changes. These must work flawlessly with all word documents. The reason is that I am currently working as an editor for a University. Because I edit other peoples work using comments and track changes, there can be no risk of compatibility problems.
If it was just my own work I would use LibreOffice, but Microsoft Word is the industry standard, and all students and faculty are supplied with office365 subscriptions for free, so that is where 99.9% of the documents come from.