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.

Good and perfect for privacy. It would be good if this were ported to Android and iOS devices

What a big disappointment. I was excited to try this out since I actually had a problem this add-on had the potential to solve: I typically use the 'Firefox Home (Default)' setting for new tabs. When I add a new tab when presenting my desktop in Teams during remote work, the tab would show icons for websites related to my personal browsing. I expected this add-on to segregate history (which, I believe, the icons depend on) by container instead of just cookies. No, it doesn't. What is the point of not 'contain'ing the history?