Beats using two browsers 5/5. Feedback
Remove "open new tab in as it wastes time"
Add reopen this tab in icon to each container. This will save the time of users having to click twice. Additionally, the icon in the address bar should not be the always open, but rather open site in a container. That way I can open youtube in the other container in less than 3 clicks.

Serviceable, but could use enhanced features to help manage and prevent unwanted cookie-cross pollination into containers. An automatic default container would be nice for any website not in the whitelist.

EDIT: Adding an extra star to this as I realized toggling "limit to designated sites" for each container forces non-whitelisted sites into the default container, preventing unwanted sites from contaminating my custom ones.

EDIT 2: Container logic seems to be confused by URLs crafted to redirect. Doing things like checking my eBay watch list or seeing my previous orders on Ali Express force containers into an infinite authentication loop whereby I have to disable designated site limiting in order for it to work.

EDIT 3: June 14, 2022. This extension is dead now that Mozilla has enabled site partitioning by default in Firefox 101. Great while it lasted but it was klugy with third party cookies and single sign-on, etc. I mean, it'll still be useful to allow multiple sign-ons to the same site, but that's about it.

great add-on, does the job well and is well integrated in the browser. Still some work to do to improve integration even further but there are regular updates. Good job folks

I've been using it for a few months when suddenly my custom containers disappeared and now I need to create them again.

FIXED: I had to log in and get it synchronized. My containers are back.

This extension is a must-have. It is very useful to separate your work/hobbies/customers so that you can use the Google, Microsoft or Atlassian suites each with only what concerns each ecosystem. All this separate from social media. I couldn't do without it anymore.

Great. Have really just got to using it a whole lot more since started new job - very good for organizing your projects. Simple, Intuitive. Stable so far, no issues. Recommended.

There are a lot of great things about this extension, but there are a few things wrong with this extension:

1 - Reordering the containers via Manage Container does not reorder the context menu when clicking on a link which you want to open a specific container.
2 - The Ctrl + Shift + # shortcut also does not use the same order, which makes the shortcut after reordering containers totally useless.
3 - Urls with paths cannot be assigned to default containers, making them very hard to use with sites that have the same root, but different authentication per path (which you thus want to open in separate containers).

These issues already exist a long time (and looking at the VPN stuff that is being added instead of fixing these) this extension will probably never work any better..

Which is a shame, because its a killer feature.

This is a great app and works very nicely with how various sites redirect you to their sub domains etc. The only thing I'd like added is
(1) being able to delete cookies and cache for a container group
(2) being able to assign different containers not only for different sub-domains, but different URI's

Not bad. The only question I would have is - can you have wildcards for "always open *.example.com" in container XYZ?

Absolutely necessary extension thanks! The only thing I wish would be to have entire windows automatically opening new tabs in the container of the other tabs of the window

Very useful

I love the idea of this add-on. It is a browser-defining feature that is a big reason why I am a loyal Firefox user.

But, it pains me to write this--Multi-Account Containers is _extremely_ buggy. The add-on crashes constantly (closing all of your container tabs and deleting all your custom containers), sometimes containers are mysteriously duplicated hundreds or thousands of times, sometimes it forgets which sites are assigned to which containers (forcing you to reconfigure them). At one point I had to delete my Firefox account, losing a paid subscription to Mozilla VPN, because MAC had corrupted my sync settings. BTW there are >700 open issues reported on GitHub: https://github.com/mozilla/multi-account-containers/issues.

But--despite being a buggy mess, I still love this add-on for what it does when it works, and for what it could be one day. So I can't give it anything less than 3 stars.