Still in Beta and currently you have to request having the software added, (Pretty easy). No extra cost or subscription fee that I'm aware of. And is sounds like they are planning to compete with the rest of Google Docs in the not too distant future. For those looking for a way out of the MS Office perpetual upgrade or subscription issues, you might have some more options before long.
https://blog.box.com/
Not sure yet how well the notes app will work for writers. But I've not been too happy with the pretty primitive Google offering. This will allow me to make some comparisons and maybe it will foster some competition.
But those of us who took advantage of the free 50 gig for life promotion of last last year will likely feel this is something at least worth looking into.