I've been using it for a few months when suddenly my custom containers disappeared and now I need to create them again.

FIXED: I had to log in and get it synchronized. My containers are back.

This extension is a must-have. It is very useful to separate your work/hobbies/customers so that you can use the Google, Microsoft or Atlassian suites each with only what concerns each ecosystem. All this separate from social media. I couldn't do without it anymore.

Great. Have really just got to using it a whole lot more since started new job - very good for organizing your projects. Simple, Intuitive. Stable so far, no issues. Recommended.

Not bad. The only question I would have is - can you have wildcards for "always open *.example.com" in container XYZ?

Very useful

This is add-on is not only amazing, it is essential.
I use it for two reasons:
1. The massive privacy boost.
2. The ability to separate my work and private life. I also use containers for finance and shopping.
Before this add-on I would have to either use a second browser and log-in to different accounts in private mode.
I love this add-on.