Subject to FF bugs perhaps... Rated 5 out of 5 stars

UPDATE:
http://forums.mozillazine.org/viewtopic.php?f=48&t=2308889&sid=ef87b4e035bec4e3547f9dddfbe916f0&start=525
So after some further reading, it appears that the issue might lie beyond this addon. Giving the benefit of the doubt, I've updated my rating back to 5 stars in the hope that the issue will be resolved and that it was unrelated to this addon. My original review remains below.

**********

This piece of software has been very useful to me over the years and I would have given it five stars without hesitation, unfortunately it seems to be dying. Fundamentally it doesn't seem to be coping with the newer versions of Firefox (14/15 upwards). Seems to routinely die trying to save sessions and will frequently re-open sessions with some or all of the tabs erased (i.e. blank tabs). This later bug is disastrous for sessions that are autosaves.

I hope the developer can get this back to its once great status, but for now I cant recommend it. I'm going to try some other alternatives again like Tab Mix Plus or something and see if they are working more reliably.

This review is for a previous version of the add-on (0.7.9.1).