Works great for keeping accounts separate. I use it for keeping my home and school accounts separate across services.

I'd love for a future update to include support for syncing containers over Firefox Sync (it's annoying to have to re-create my containers on each device I use).

Also, the current interface for opening a new container tab seems kind of clunky. Having to hold down the "+" button is unintuitive and takes too much time (what can I say, I'm impatient). I'd much prefer having multiple "+" icons next to each other for each tab. Perhaps color each button the same as the corresponding container to make it even more intuitive.