The reason I'm pushing this to be the main O2 GUI for now, is because I think it is a a better representation of O2 than the current v1.4 GUI (and I use this GUI every day, so it's starting to be quite solid :) ).
The v1.5 of O2 is still under development and will be based on TiddlyWiki which is an awesome 1-page Wiki engine. You can see it in action if you click on the 'v1.5 GUI (TiddlyWiki based)' button of the 'Custom O2s' Tab, and it currently looks like this: