Usability wise and task wise: it is to the point and does exactly what you want it to do.
Accessibility wise tho? Not so much. The only thing that would make me bump it up to a 4 or even 5 star review would be if the tabs could be synced to other devices or to your Firefox account you use to sync tabs and the such. There have been many cases where I had to clear cache because something was acting up or my cache was just bogging up space and lost my tabs as a result of said clear.