I recently made the transition back to Firefox too, like a lot of other folks in here it seems. Containers makes working with all my AWS much easier, and the containers isolating Facebook are great.

One problem though, that I can't solve, is that every once in a while I want to log in with Facebook, like for AirBnB. But I can't, because the cookie only lives in the Facebook container, but I can't add AirBnB as a hostname to the Facebook container.

Has anyone solved this?

Edit: I just solved this. You have to disable the built in Facebook Container extension and then it works as expected.