Works great, but sometimes I forget that when I log in on a Google account for a different website I need to open my separate tab.

Great idea, lazy execution.
Often fails to contain certain sites in their containers, popup for confirming a site be exclusively handled in given container sometimes unusable. Containers are a single flat list.
All that is minor, for an official addon it cannot sync settings, and settings are partially lost when disabled. Sites contained in default containers will be remembered, custom containers permanently lost.
If you are going to delete everything on disable (not remove), for any reason, at-least be thorough.

TLDR: Bare minimum functionality, still buggy. Is being an example an excuse for being poorly done?

Di base è ottima ma è troppo limitata. Oggi ho perso tutte le preferenze e non posso recuperarle. Per favore aggiungete il backup, inoltre non è possibile selezionare da menu i siti salvati, dovete creare una UI decisamente più completa e che permetta di personalizzare i domini aggiunti.

I would love to see some sort of way to save my preferences about which sites open in what custom containers, e.g. save it yo my firefox sync account, or save to a simple text file, or to some cloud storage or in whichever way that seems most applicable for this sort of data

Easy and straightforward way to keep different browser contexts separate.

great - but today all my containers disappeared and default 4 were present only !!

The add-on idea is pretty great, but it does have a lot of bugs. An option to have shortcuts for each container would be nice, also when the Firefox browser refreshes itself, my containers are lost and I have to create them all over again which is pretty annoying. More icons for the containers would be welcome

Great idea. Too many bugs.

Works great until all of the container configuration disappears and it for some reason reverts to the original four default containers it comes with upon installation. I hope it gets better. It is pretty frustrating to recreate ~10 containers and assign dozens of web sites to each of them more than once.

Works when it works.
The problem 1 is, it opens all links from a container in the same container, you can not setup "default container" rules. (eg. google.com is in container A for a reason, but I want to open search results in default container so websites can be normal). Nor can not setup strict rules (eg. ONLY youtube.com is in container B, and all other sites will go back to normal)
The problem 2 is, no wildcard support. So if you want whole "Google" in a container, you have to setup rules like: drive.google.com, keep.google.com, image.google.com, maps.google.com etc.etc.etc. Instead of " *.google.com"

Easy to use, Very effective. An essential add-on.

this works great

Extremely useful feature.

Ich verwende das AddOn jeden Tag, da ich oft mit unterschiedlichen Accounts auf der gleichen Webseite angemeldet sein muss und nicht Lust habe, unterschiedliche Browser zu verwenden. Den 5. Stern bekommt das Tool, wenn man in Ordnern der Lesezeichen-Symbolleiste Favoriten gleich so abspeichern kann, damit Sie wissen, mit welchen Container es geöffnet werden soll.

There are some problems and missing features:

- different number of icons in firefox setting and plugin setting
- need more icons e.g. email
- open this site in assigned container doesn't work
- multi language support e.g. german
- sort containers themself
- in firefox setting is missing whitespace between icon and text

This is much better than managing different profiles. This is more practical. Profiles have separate DB for stored passwords etc., which is annoying.

To make it easy to use, the Firefox team must work on easier short-cuts for container, container-tabs, default window for containers etc.