I've used LaTeX for years, written part of a textbook and a whole dissertation in it, and I don't like it.

There are two good parts to the TeX ecosystem in my opinion.

  - Typesetting math formulae. Even Word agrees that it's superior to point-and click for this use case (unlike our Blackboard online learning environment ... *sigh*)
  - Plain-text based. You can use your favourite editor, you can put it in version control, diff it, etc.

But for writing text-based documents such as lecture notes in subjects that are not mathematics, I really don't feel comfortable with the usability. For example,

  - Getting figures, page breaks etc. where I want them.
  - Underlining things is suprisingly hard (and not intuituve).
  - A marco preprocessor that has many of the disadvantages of that in C.
  - Confusing error messages, stuff randomly doesn't build.
  - Package X doesn't work with package Y (unless you include package W with option Z first) type problems.

I would switch in a heartbeat if there were something with the advantages of TeX, but not the disadvantages. It seems to me like neither of LaTeX3, luaTeX or XeTeX has got enough traction to get everyone to switch.

For things less than 50 pages or so, I've actually moved back to word, which if you buy the proper version rather than the 365 one is surprisingly good. I've found that in practice, for things where I care a lot how they look (which is pretty much everything), unless it's very mathematics-heavy I get the job done in just over half the time in Word usually.