Re: @BongoJoe: Word isn't the best tool for job
That rather suggests that you think there is some other software that is the best tool for the job. So, what is it?
It think the challenge is the downstream publishing process. The actual writing can be in anything that works for the author (more accurately, doesn't get in the way of the flow of the creative process), but it then needs to be presented in a format that allows markup and editing.
As I work on OSX I use Ulysses and Daedalus on the iPad for when I travel (they integrate to a reasonable degree). The apps go full screen and allow me to exclusively focus on structure and content creation, but stay away from styling which is IMHO one of the main problems and distractions with WYSIWYG based writing - basically, the whole reason many people still use LaTEX and derivatives.
I also use LibreOffice, mainly for short work and for mapping writing into some form of design template so that the Word addicts of the world don't get frightened by hints of something outside that narrow band of experience.
I don't create much on the iPad unless I have a bluetooth keyboard with me (I'm no fan of screen keyboards), but it's good for post production review and small edits.
So there :)