I really enjoy the Containers. The only problem is that you can only have a single container tied to an individual site. I'd rather like it to be tied to a subpath or url "root" so I could use it with GitHub.
I recommend the Search and Switch container[1] extension for that. You open a new tab, type 'co <container name' and it reloads that tab into the given container. For example, I have a container for all things Google, called "Google", and the extension use would go like this 'co google', or even 'co goo'. It's smart enough to figure it out.
Plus, you can also move existing tabs into a given container the same way, not just new tabs, all at the cost of a single tab refresh.
If a person wants to test a website using several accounts in Chrome, they need to open and manage several windows. Lame.
If a person wants to access an ad-ridden website using several accounts in Chrome, they need to install, configure and maintain all of their favorite ad-blockers and anti-tracking extensions in several Chrome profiles. Lame.
In my experience, people who prefer profiles over containers are mostly casual users who don't configure profiles and use maybe one or two extensions.
Mostly, you can't have different profiles in the tabs of the same window in Chrome, and you can have different containers in the tabs of the same window in Firefox.
E.g. you can run your email tab in the default container, and a bank app in a separate "money" container next to it.
Or you can run one gmail (or outlook, etc) account in one tab, and an another gmail (or outlook, etc) account in another tab next to it.
Also if you only want to separate (log-in) cookies, local storage and that kind of things for certain sites, but don't want separate history, bookmarks, settings, add-ons, etc., which is what you'd also get if using completely separate profiles.
First, I'd like to point out, that Containers are built-in with Firefox, even though you generally want at least the official add-on for ease of use.
Containers were actually the reason for me to switch over from Chrome about a year ago. The biggest benefit I see is that they're made easy to extend via add-ons.
In my set up I currently have a new container created every time I open a new tab, either blank or from a link, and automatically removed after I close them, which is made possible by Temporary Containers add-on in auto mode.
This creates automatic boundaries for all of my browsing. I then also have persistent containers for sites I want to be logged in to.
