Ok.
I hadn’t come across it before and it was only inadvertently in this instance: The documentation of an app build was created using it. But outside of the supposed tight connexion to GitHub, there seemed little else really to recommend it.
BTW, once again, I urge paying a local tech writer to be a stenographer/writer for a few days, if only just to get the work started. One could also use OS X’s dictation tools—that works, btw, esp. for doctors, I’ve discovered, who must constantly write the equivalent of guides/reports for themselves, insurance, colleagues; and these are life/death words—but would also lead you, I’d guess, into a maze of tweaking.
-louis