It's good but I wish there was a way to put always put all subdomains of, say, google.com into a container automatically, instead of having to add a rule for each subdomain separately.
Ublock Origin and similar add-ons allow the use of wildcard characters which make it easy to filter all subdomains of a site at once. It would be good if this functionality was added to Firefox Multi-Account Containers.

Essential to segregate cookies from Google, Facebook and other spying corporations.

Life saver especially when using multiple Office 365 Business Accounts!

This extension is great to use multiple accounts or profiles at the same time.

this is BS... I just want to sometimes use a container, for some websites... but I clicked "something" and now youtube always opens in the personal container!? I don't want that though... I want to use youtube normally, without a container and there is no option for that! wtf

Works as intended. I can now contain spying websites on their own sandbox and use M365 on multiple accounts simultaneously.

Simply awesome

Can someone explain to me what's the difference of Multi-Account Containers with the new site isolation feature in Firefox? Is it still useful to have the multi-account containers?

Such a useful extension. I'm a freelancer who works part time for four different companies, all of which have onedrive and sharepoint sites plus other systems. Being able to simply open onedrive/sharepoint etc in the 'company 1' tab then the 'company 2' tab and have it log me in to the right place automatically without hassle is a massive time saver and so useful. Love this extension.

Awesome to separate your buying from banking etc.