Just to be clear, this is NOT just a simple UI version of profiles. Containers only separate Cookies, localStorage, indexedDB, HTTP data cache, Image Cache (bug in progress), and other areas supported by originAttributes (See https://wiki.mozilla.org/Security/Contextual_Identity_Projec...)

I.e., Containers do NOT protect against some lower-level privacy vulnerabilities like plugin enumeration or history-sniffing that are mitigated more by using entirely separate profiles.