It's very useful to be able to keep my accounts separate, both from a business perspective (multiple google/microsoft accounts), as from a privacy perspective (all google or facebook tabs in their own containers). It may be a bit of a hassle to set up, especially since you have to set it up separately on each device. Once it's set up, it works really well, always opening websites in their assigned containers. I would like to see a sync feature, and the ability to reload the current tab in a different container.