Update Dec 2020:

Facebook has found a way to track around it, I've been getting ad's for stuff I just browsed again.

Original review:
To all the people complain it breaks other websites, that's the point of the container! It's to help stop facebook from spying on you everywhere you go, blame the broken websites for requiring facebook to log in or implementing their tracking bugs.

Review: It works great for me, every since I started using it I'm noticing a lot less targeting advertising on facebook from things I do elsewhere.

first thing is why it needs my username and password? others will be available after the answer/

Having read the blurb I liked the idea of the fence warning me I was in the facebook realm. I went to facebook.com and the fence didn't know this was part of facebook. Not a great start.

This add-on prevents login to Chase credit card site. Ever since this add-on went active in April, I have been having numerous and annoying website issues. I have disabled Facebook Container and have not experienced any problems since disabling. This app is a headache and should be quarantined until properly debugged and peer-reviewed. (CPU: I5-2330M, RAM: 12Gb, OS: Windows 10, 64-bit, Browser: Firefox 76.0-64 bit)

MANTAP, SANGAT BERMANFAAT 👍😊

It works on facebook but broke a few other websites.
Menu bar on the NY Times Coronavirus page (https://www.nytimes.com/2020/05/02/us/politics/vaccines-coronavirus-research.html) broke.
It also stopped mint.com from tracking my computer, so I had to authenticate with my phone every time. Both websites work when I uninstall the plugin and reset firefox.

While I love the idea of this extension, it causes too much breakage on certain sites. For example, this extension breaks Sharepoint online or any other site inside of Microsoft 365/Azure that has an embedded Facebook widget. It causes the page to get stuck in an infinite login loop if you try to allow the widget or causes the page to display incorrectly otherwise. Not recommended if you use Firefox for work with Microsoft 365.