In order to find the least common denominator between all the platforms, you gotta pick the app and the file format that will work everywhere. That’s where Dropbox jumps in, providing you an ecosystem that will work from the browser as well as any platform. Dropbox works fine on Windows, Mac and even linux.
Ultimately I already made a choice of sticking with Dropbox and writing apps ecosystem around it. This Provides enough of the variety to make it worth a while long term.
On the other hand Editorial is quite powerful and I need to give it a go, and I am quite sure that I can get something out of it. Writing after all, is a job you do on your iOS device.