Love being able to keep things sorted out into categories, and the segmentation of all the tracking data sites collect is a nice bonus. The setup process could be a bit easier (getting all your common sites sorted) and I would appreciate a way to completely disable the "default" container. Also this NEEDS sync support. Each device I use FF on I have to recategorize all my sites. Mobile support would be cool also, but I'm not living and dying for that one.