Needed to hop onto Firefox while Chrome was being a bitch, and this add-on allowed me to replicate Chrome's groups... somewhat. How to switch between groups took a bit of getting used to, and it's more helpful in some areas (i.e. creating groups) and less in others (quickly switching between groups). That alone would be a 4-star rating, but what drops it down is the difficulty of organizing tab groups in the groups tab. I can only organize it alphabetically, so I have to go through some hoops if I want my groups in a particular order, which is fairly annoying. All in all, a helpful add-on, if not exactly what I was hoping for.