This is really useful for having multiple accounts. Per-site containers could be a nice addition?

This is a great add-on that has improved my workflow immensely. It allows me to easily separate multiple accounts on same sites both between personal and work, as well as within each of these life domains. Saves time and keeps cookies separate, too. Sync between different machines could stand to be improved a bit, in my experience, as any new containers a make on top of the default categories don't seem to sync to my other devices. Still, this is only a minor issue for me, and not enough to take a star off. Recent improvements that allow you to choose where to open a site with right click, and to reopen a site in a different container have also been very welcome.

GREAT

It is useful to distinguish works and personal by tabs

I love this addons

Too good, I meaning, super useful tool. Thanks to the mozilla team!!