When I tell people that I don't use Microsoft Word, they are generally somewhat taken aback and then assume that, because I own a Mac rather than a Windows PC, that I just use Apple's Pages instead.
In fact, I don't use any kind of conventional word processor. I also don't use PowerPoint for presentations or Visio for diagrams. Instead, I use what's known as a 'typesetting system' called LaTeX.
You can read all about the LaTeX project on their website (http://www.latex-project.org/) and there's a fairly comprehensive description on Wikipedia (https://en.wikipedia.org/wiki/LaTeX). I thought I'd write a few simple words on why it works for me.
Style and Content
LaTeX allows me to separate the tasks of writing content and deciding how it should look on the screen or printed page.
My content resides in a simple text file with no formatting whatsoever. Anything to do with presentation is held separately (again, in a simple text format) in a file that defines the style for the document.
That's important to me. If I'm in the middle of distilling my thoughts into words on a complex subject, I don't want the distraction of dealing with fonts, colours, sizes, margins, page breaks or any other presentation aspect. I want to concentrate entirely on the words I'm writing.
Longevity and Portability
I'm old enough to have documents dating back to the late '80s and early '90s that I originally wrote in WordPerfect or Lotus Ami Pro long before Microsoft Word became a mainstream tool. Over the years, I've had to convert those from one format to another, with varying degrees of success, or maintain software that I no longer actively use simply in order to access those documents.
I grew tired of that some time ago!
LaTeX content is stored as simple text files - just about the oldest file format of them all! I'm guaranteed to be able to access it long into the future on any machine I'm likely to own in my lifetime.
Tools and Tasks
Since LaTeX content is stored as simple text, I can use any text editor I like to manipulate it. I can change my mind at will and not have to worry about converting anything if I move from one editor to another.
Some of the best text editors out there at the moment are either free or very low cost and several have plugins that allow me to complile my LaTeX documents to PDF files with simple keystrokes within the editor itself.
I use the same editor for all my technical work, so I only have to be familiar with one set of tools.
LaTeX allows me to produce all kinds of documents, including presentations, so there's no additional software required when I want to throw a few slides together for a talk.
Collaboration and Version Control
The tools available for collaborating with other people are first class and a long way ahead of anything that might come with a conventional word processor. They come from the world of software development since most software code is also stored as simple text files.
Collaboration can sometimes be tricky. If I'm working with people who are familiar with technical tools like git and github, it's simple to introduce them to LaTeX and the collaboration is straightforward.
However, if I'm working with someone who has never heard of git, never used a text editor and is firmly wedded to their copy of Microsoft Word, it's much more difficult. I can end up spending more time teaching them how to use the tools than writing any content.
I don't have an answer to that one yet, but I'm looking at online tools like Overleaf as potential solution.