Since buying a new MacBook a few months ago, I've been trying to use Circus Ponies Notebook for my outlining needs (Apple phased out OS9 in Leopard, so InControl won't work on that machine 🙁
Jayson Adams of Circus Ponies has created a very impressive product with Notebook and watching him demo it a MacWorld in San Francisco back in January sold me on buying it. Overall, I'm pleased to have his software and all the things it can do. Unfortunately, what I want to use it for primarily is as a simple outliner and 'brainstormer' like my old copy of InControl was.
As an outliner, Notebook is really a very different experience than InControl and so far, I'm just not getting the hang of it (sorry Jayson). It'd be great if there was a way I could customize Notebook to mimic the functionality and layout that was InControl. For example, to add only those features I wanted my outliner to have from a master menu and build the outliner from the bottom up (Drupal modules comes to mind). Maybe someday.