Indispenseable! Rated 5 out of 5 stars
I use a lot of organized, nested bookmark folders right in my Bookmarks Toolbar Folder and this nice little add-on lets me organize my bookmarks as I add them, by allowing me to quickly put them right where I want them to start with, vs. opening up the bookmarks sidebar and dragging and dropping.
Now, I rarely need to use FF's Organize Bookmarks feature, other than to periodically clean out dead stuff.
Awesome little time-saver!