Lightweight Alternative to Tab Mix Plus Rated 5 out of 5 stars
I have used Tab Utilites for a few months before switching over to Tab Mix Plus. Aside from the session manager built into TMP, both offer relatively the same options. The features that TU offers over its competitors are the toggle buttons allowed on the add-in bar and a myriad "hidden options" inserted into the preferences.js file(about:config). My personal favorite toggle button was the "Open all links in a new tab," which made browsing forums very easy.
I will rate this product with five stars. Reasoning, despite my personal preference, is that it's a very powerful albeit lightweight tab manager that's updated often.