This add-on works great: I can keep an extra container for google, amazon and netflix while browsing in a different container without these companies recognizing me!
To me, it is basically a better controllable version of private browsing.

Functions exactly as advertised. I use it as an alternative to the "tab groups" in google chrome. The containers also sync across devices(not on Android, ios I don't know) so that's pretty neat.

I also recommend "facebook containers" which use the same underlying tech to keep everything facebook in a separate sandbox

Lots of power when you need it, basic tab containers when you don't. Sane defaults. Seamless integration with Firefox containers and Mozilla's VPN.