I am really enjoying this container tabs add-on, it has a very useful functions such as separating accounts, defining a specific container to open specific websites, hiding an specific container...
The reasons I'm not going full 5 stars here are in my next paragraph babble, but it's still a REALLY GOOD add-on!
I'd love to see just few more features such as sorting container tabs in new windows and being able to "mute" or "offline" certain tabs without hiding them (and also the I could choose what tabs to un-hide and in which - or a new- window) much like how you used to be able to choose what to restore after a crash. Being able to open bookmarks on containers also, and setting up a default container... Also, being able to save settings with my firefox account for cross-device ease and consistency!