I love the concept! It's private, easy to use, and should be BUILT IN to Firefox! I just wish you could add more icons, each container has it's own individual history, passwords, etc. Also, when I sort the tabs, it moves the new tab button to the left, and I can't change it back, which is annoying. What would be nice is if I didn't have to open a new tab in a container by having to go to the container menu. If it would be right next to the new tab button, where everyone would see it would be awesome. Overall, great!