とりあえず、入れておけば他のブラウザやFirefox自体のプロファイルの使い分けを減らせるので便利です。
欲を言うと、次のような機能があったらいいなと思います。
・メニュー上のコンテナを任意の順序に並び替え
・ステータスバーから新規タブを開く際のコンテナ選択をするかしないかの設定
・タブやページの標準コンテキストメニューでコンテナの移動やコンテナ別新規タブのオープン

更に欲を言うと、タブリストボードのようなタブの一覧をグループ化して表示するアドオンやセッションマネージャーと一体化し、一覧ページ内でコンテナ別に表示して、まとめてブックマーク、まとめて閉じる、以前開いていたタブをセッション付きで復元と言った操作を簡単に行えたら最高ですね。

Fairly good, and certainly an improvement over one of the few features that kept me on Chromium/Chrome until now. Being able to sand box tabs is quite useful for the sites (social media) where I have multiple accounts, now I needn't log out/log in to use them, and it even helps with sharing.

Hopefully we'll see improvements in the future, I for one would like to see more control over the default container, and would like an easier way to select the container than the current button/list (ctrl+c1/ctrl+c2 perhaps?).

EDIT 3 NOV
Still liking this, but seeing one area that could use to be improved, it'd prolly be a good thing if the highlights section of a new tab was restricted to content previously seen in that container.

Yet more distracting screen clutter. This add-on is as bad as all the unwanted advertising that most of us banish with the excellent choice of Adblockers offered by Firefox. I know exactly why I'm visiting regular websites, whether it's for shopping, banking or other purposes. What is the point of this?

LOVE!! needed this and I tell everyone I know about it!!

Great work team!!!

I really appreciate this extension! However, some essential features I am missing include:
* Ability to sync settings. I've recently found myself having to delete and recreate profiles to no end, troubleshooting an issue with another extension. Reassigning my banking sites to the banking container, my email to personal, etc., etc. is fun the first time, tedious the 3rd, and frustrating past that.
* Ability to automatically open a site in another container. For example, I forget to FIRST select that I want a certain container, I just go to the site. Oops. Now I have to open the correct container, then go copy the URL and paste it in. Would be great if we could right-click and "reopen" in or "move" to a different container.

I'm certain I gave feedback on the first one some time ago somewhere, but can't find where that was to follow up. (email? Twitter?) I'm finding myself about to recreate a FF profile again, and even just being able to save my current settings and then manually reapply them would be a good workaround at this point...

Brilliant add-on, a must for multi-tenancy cloud admins.

wow love wish i had this yr's A GO NOW I HAVE ms. it,s slow me down i well tell all i can and tell to pass it on if was old man that fell in a gold mine make fell like landing Down cry Tell All FireFOX is the way to go

Tab hoarders unite! (I'm pretty sure that because of the multi-account component, this isn't what the original creators thought would be its use but hey, it works great for it as well)

I honestly love this extension, but I couldn't give it that last star. There's two or three things I would love to see updated for containers that would definitely earn that last star though: switching a tab to new containers from either no container or a different container (one at a time or en masse), as this would allow first time container users who hoard tabs to move them over a little more easily; the ability to shift around containers (i.e. move up a container that's in constant use up, or move one that I don't really care for down), as currently the only way to "move" them is by deleting the container and then making it again which puts it at the bottom of the list; and if you could make it so that tabs in a closed container (or open for that matter) would sync with firefox sync (and the containers themselves!). These changes are the only things getting in the way of this being from my perspective the ultimate tab sorter.

Containers has honestly helped me organize my online activity and helped me put my distractions into a side tab, though; so I honestly say this is one of, if not the, best add-on on Firefox, which is (in my incredibly biased and tab-hoarding opinion) the best internet browser.

It takes a little geeting used to but the add on makes it really easy to isolate specific accounts. For example I open all the google websites in a google container :) And there's another add on specifically for Facebook :)

Fantastic desktop application. I would love to see it made avaiable for Firefox on mobile.

This plugin makes my life so much easier toggling between my many projects. Just wish firefox comes up with a way where we can sync the containers with our FF profile. Great Job FF Team!

One of the best extensions, one more reason to stick with FireFox!

Works flawlessly - I love it!
Prevents Facebook and Google from tracking everything.

I like this add-on! I use it for multiple Google and YouTube accounts and it works well! That's so convenient! Good integration e.g. it can open tabs in a container from the top sites page and from the Firefox - File menu. It would be nice to have an option to access the Containers' menu via right clicking on an opened tab (for accounts to be switched automatically if it's technically possible). Or even via page context menu. Also hotkeys would be very handy for some users. Anyway, many thanks to the developers for this very useful add-on.

Works pretty fine.