Containers is simply amazing for the work that I do. I maintain electronic accounts and services (web, email, domain, etc.) for many different clients. Before containers, I would often need to either log off one account to log on as another, or open several private tabs. Now I keep one container for each client, meaning cookies and session info stay present. Whenever I need to make a change, I simply open that client's container, head to the right service, and everything's already logged on and ready to go. I only wish a) there were more icons to choose from, and b) there was a way to sort container names (not the container tabs, but the container names themselves) in the GUI. But if you handle multiple accounts for the same web sites, this add-on is a godsend.