Excelente, al principio hay que ir seleccionando que pagina va con cual contenedor, pero despues de hacerlo es super simple ya que se abre automaticamente en el contenedor.

This is THE best feature of Firefox IMHO

It's easy to use to help organize tabs! The ability to have tabs/websites auto open into their respective containers is great!

Lovely, simple, and effective :D

It takes some time to assign the most frequently visited sites onto the right permanent container, and to rewire muscle memory to open sites as containers. But once over that hump it's a truly amazing and lean add-on!

It helps a lot since I need to change frequently between my personal and work Google accounts. I won't need to open different browsers any more.
Just a small bug that when I chose to open the links in my Gmail, this add-on would somehow change the original redirect link and get me to the wrong page.