FF Quantum - Killer Feature Rated 5 out of 5 stars
I cannot tell you how much I rely on tab groups at work and at home.
I'm seconding @red2001tj comment. With the arrival of Firefox 57 (quantum), Firefox's performance will hopefully be on-par with Chrome. But the tab groups addon will be the killer feature that puts it on a level above Chrome.
What do we, as a passionate community, need to do to keep this project alive?