Rated 4 out of 5 stars
After some months of heavy use of this tabgroups, with other 41 active addons, there has been very few problems so far.
Occasionally (very rare), after session is restored, one or two groups there is tabs that are completely unresponsive e.g. clicking them does not do anything etc. Restart usually seems to fix this.
Also i've yet to discover how to control what page is opened when new group is created with the default single tab open. For awhile it was my "fast dial" addons page (weird), now it's blank. I've got TabMixPlus set to load new tabs to homepage but it does not seem to work with this(?).
Overall, this addon plays nicely with other addons, as i already mentioned, i've got "few" other addons installed on my current profile.
I'll give it 4 stars, maybe i'm too picky but theres some room for improvement. In any case, THANKS!