I am a fiction writer. I have used a dozen or so writing packages.
Focused does one thing better than any other. With Zen it is the best immersive writing environment - simple, clean, non-disruptive.
Still I can not recommend it. I can cut and past to MS-Word for more advanced features, but the lack of an indented paragraph means that I have to go over every line after pasting to MS-Word ti input paragraphs. More attention to this feature would make it my go-to program for long composition.