At the moment it is the best add-on for handling tabs in sessions when you also use containers. In other session tabs add-ons a session restore moves all tabs into the default container - I had 15 containers and approx. 350 tabs. It takes hours to move the tabs back to the right container - also because I did not found a good tool for "mass moving" tabs to containers. I had to do it one by one.

I made a littel test with the export / import function of session boss - it works! It did not crashes my tabs and containers. But importing into an other firefox (dev) does not work...I will ask the developer.