very useful

Highly recommend this - great for managing multiple accounts (e.g. mail)

Excellent.

A fundamental feature

It's hard to give a review for this, because the effect can be hard to see. However, being able to separate different websites into different containers is really useful for when I'm multi-tasking and trying to use multiple accounts at one time.

Also, I think I've noticed less scarily intrusive and stalking ads after separating the accounts and cookies into different containers.

Very convenient