Rated 4 out of 5 stars
Categorize version 0.9.6.16 corrected a previously annoying little bug (conflicting with another extension), thank latif you for taking care of this!
As for previous reviews, it looks like they were pretty unfair:
1. takes over far too many aspects of the UI for my tastes. Well yeah, everyone's free to like/dislike, install/uninstall ;)
2. I simply check "Keep Firefox Bookmark toolbar" when installing Categorize; thereafter I keep all of my quick links in the usual bookmarks toolbar, as well as the ability to add other semi-bookmark buttons to the toolbar :-)
3. By default, it also takes over the Search Bar, removing my carefully-chosen search engines: Well then just choose to keep Default Search features when installing, and that's it.
4. This plugin lasted all but 50 seconds before I uninstalled it. Sure, this is a powerfull extension, real different way of organizing one's bookmarks. So yeah one needs more than a few seconds to take profit of it...