Rated 5 out of 5 stars
Love this add-on, not fond of version 0.3.8.3.
Like -Fatal-, I switched back to 0.3.8.2 (if you're wondering how to do it, it's in the "View All Versions" link at the bottom of the page).
P.S. Even though I always enabled "show on tab -- close tab button", the little "x" icon didn't appear on the tabs in version 0.3.8.3.
All that having been said, I adore Tab Mix Plus! The tab functionalities and its ease of customization merit 5 stars in my book!