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.