I use it every day, I cannot surf without this extension anymore!

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So far so good. Nicely done Mozillians :-)

I have tried this addon on two of my laptops. Both systems stops responding shortly after installing and remains in hung state for around 20 minutes, then firefox crashes and system comes back to life.
using ubuntu 20.04.
Edit - Now that i have deleted add-on. it is still showing container option in right-click menu!

Одно из самых полезнейших дополнений. Очень удобно для использования одних и тех же сайтов из одного окна.

Cette extension est un compromis parfait entre la sécurité absolue (1 onglet=1 session) et la performance (n onglets = 1 session). Je sépare ainsi mes onglets par groupes: "Personnel", "Professionnel", "Finance", "Transactions", "Google", "Facebook" et "Suspect". Cela me permet, par exemple, de rester connecté à mon compte Google sans rouvrir automatiquement la connexion à chaque redémarrage. Un module indispensable pour moi!

so much better than the Chrome's multiple people feature. Thanks Firefox.

So disappointed that my containers (except the default ones) just randomly disappeared today. It could be because I clicked a button in User-Agent Switcher & Manager which said something along the lines of - use/connect Multi-Account Containers - but now I'm so mad because I have to recreate the containers. My rating (before this incident) is actually 5-stars. They've also made it easier to "Always open this site in..." a container which makes setting up more convenient.