Rated 5 out of 5 stars

Great alternative to Tree Style Tabs. TST kept messing up the order of my tabs when Firefox was restarted, so I just switched to Tab Utilities. Although there is no "tree" function, it does a good job of displaying the tabs vertically.

This review is for a previous version of the add-on (1.5.27.1-signed).  This user has a previous review of this add-on.