This add on is faster than other vertical tab manager.
Very promising, it just lacks the coloring of the tabs by group for me to adopt it.

Has the most options of any addon I've used!

This extension is EXCELLENT. Much better than the old Tree Style Tabs. Faster, more full of neat features. It's great. I never write reviews, but this one deserves it.

Amazingly intuitive and full-featured tab management. Wonderful integration with other Firefox features, like containers and bookmarks. Full tree structure with everything you'd expect plus unloading, saving sessions (as "snapshots"), and very rich customization support.

nice and simple