I like idea that Mozilla tries to move some of the power user functionalities into add-ons making the browser more lightweight by default.

But I really missed this feature, when it was removed and just found this add-on today.

Can't sign in using FB oauth on other sites when inside container

It's almost a 5 start review. I would appreciate a streamlined way of opening new tabs in a container. And maybe, if at all possible, having a setting that would allow to open links coming from certain apps in specific containers would take this extension to the next level.
Otherwise it's a great tool to keep my multiple work account that depend on gsuite login apart from one another and (for the most part) always logged in inside a particular container.

The icon not appearing in my browser. I can't find the setting to enter the Dashboard. So bad

I love containers, hope they will be here for ever

Isolation of trackers, always a good thing! Would be 5* if it were possible to manage the stored data for a particular group of containers, Shopping, News, Google, etc.
A news site that downloads 50 or more, highly intrusive and persistent cookies and trackers will need "cleaning" far more than my "Work" tabs that are typically Linux and FOSS technology which (in the main) seem to use minimal cookies.