I used to have this Addon on the Chrome Browser. Now I tested it yesterday on Firefox. The only feature that this addon is lacking, is the <> to find Tabs Quickly. And the ability to separate Tabs into several Groups. For Example: YouTube Group (with all the video tabs), Design Group (tabs for design websites), etc...
Because I have more than 1000 tabs open So I can not find easily what I want. I will update my review when They add these two important features.