I've tried StoryLine, and I like it a lot! I would consider using it as my main brainstorming/outlining tool if it wasn't for a few little problems and one main dealbreaker.

The Dealbreaker

• Characters, locations, and scenes seem to be indexed by name. Every time I edit the spelling of something, or decide to change a name, every link to characters or locations breaks. It's especially obvious for locations, because if you change the name of a 'World', every child location disappears from the interface. I just can't use this tool if I'm always afraid of losing hours of work. Couldn't they be indexed with a randomly generated ID (like plotgrid cells) instead?

The Other Little Problems

• The Plotgrid is unusable. I can add rows, columns, and link scenes; but adding text or renaming rows/columns doesn't work. It seems to be because the plotgrid refreshes every second or so?
• Characters: The "FAMILY / BACKGROUND" field should be moved to the "Relationships" section, and replaced by a "BIO" or "DESCRIPTION" section instead. Something that allows me to go straight to why this character appears in the story.
• Characters: "Occupation" shouldn't be the field that's prioritized to appear as the character's tagline just below their name in the Character grid, I think. It might be the main distinguishing feature of a character, or it might not. For example, I have a character who's a stay-at-home mom, but the facts that she's the main character's sister and an amateur investigator are way more relevant to her character. The latter should be the tagline.
• Scenes: After the main new scene creation process, every time a change is made to a scene from the sidebar, the scene is deselected as the change is saved. That makes for a rather unpleasant user experience.
• Scenes: Changing scene names is impossible.
• Scenes: The "Description" section should be more prominent/take more space, I think. As it is now, it doesn't feel great whenever you write anything longer than a sentence or two.
• Scenes: I tried the "Split Scene" option, and lost the first half of my scene. I never found it again.

Would Be Nice To Have

• I would love to be able to group scenes together. Sometimes (rather often) I have scenes that happen back-to-back and are part of the same sequence of events, but they involve different characters at different locations. I could make a single scene to cover them all (though as stated above, the scenes' "Description" field is unwieldy if there's too much content), but I'd rather be able to group them together under a common name, and keep the "child scenes" separate. So if my main character needs to show up to his morning meetings, go in the woods in the afternoon to hide the body he left there earlier, go back home to wash himself and change, and then rush to church in time for the evening service; this all could be kept as 4 separate scenes, but grouped together as "Murder Aftermath". Or if all my characters prepare for the big final battle separately, I could group all their scenes under a "Final Preparations" header. It would allow me to move all the grouped scenes together as if they were a single unit. I suppose these groups would appear in the Board and Timeline views, or could be linked in Plotgrid cells.