I used this the other night to get a long-gestating story out. The multiple-timeline view is fantastic and really easy to rearrange intertwining narratives. It's more sophisticated approach than Scrivener's corkboard and more flexible than a physical corkboard / index cards without having a whole lot of spare floor or wall space.
Also, there's no need to have all your timelines arranged chronologically (although naturally that makes sense), as these work just as well to plan out your story beats in a non-linear story. I didn't venture too far into the other features as they're reasonably well represented in other apps.
What I think would take this to the next level is if the story nodes/beats/scenes/chapters/whatever had multiple levels of granularity, so you could organise your timelines from a high level, then move into more specific breakdowns, until you decide you want to get into the actual prose for that breakdown.
DoodleLens
Project Palette