Love this tool. I was frustrated with Workflowy, and am using this to outline my writing projects before dumping to Scrivener.
I do have a problem with some of the keyboard behaviors. The one that prompted me to drop a note is the behavior of the Enter key. If I am on a bullet with expanded subpoints, hitting the enter adds an additional subpoint instead of creating a new bullet of the same hierarchy of the bullet I started from. If the subpoints are collapsed, the Enter key does add a new sibling bullet, skipping the subpoints entirely. This should work one way or the other (preferrably Enter creates new sibling with a combination key for new subpoint).
Apologies if this has already been covered.