I've tried to switch to Markdown almost completely for portability, but I end up having to return to Word frequently to accomplish certain features. IMO, Markdown's biggest flaw was that the original feature set was incomplete, and everyone has tried to fill in the gaps (TOC, tables, references, etc.) their own way instead of settling on an updated standard. That makes it really frustrating when I've got to rely on GitHub-flavored Markdown to accomplish something without being able to trust that it will work on a platform that only supports vanilla Markdown, etc.

One thing I will give Word credit for, despite all my qualms with it, is that it's probably the only program that I can blindly paste something from my clipboard and expect that Word will render it reasonably well.