Hope I haven't missed the answer to this somewhere... I did search the forums and Google....
Just purchased and tried Storyist on my first generation iPad. Looks nice.
One problem/aggravation.... while pinning the outline so that it displays on the left and a full editable page view displays on the right works in landscape mode, it doesn't work (isn't pinnable) in portrait mode. No pin icon/button and if outline is displayed, can only see right portion of the page view and if attempt to edit page, page takes over the screen, shoving outline out of sight.
I'm guessing this has to do with the first generation iPad's iOS version (5) or its lower resolution.
Does this work on an iPad Air with Retina display and iOS7?
I.E. Can I write in pinned mode in portrait mode/view on it, with both pinned outline on left side and editable full page view to right?