I'll spare you a lot of reading, as most everyone else has touched on this extension's many features and usability. I will add that I like how visually appealing the tight spacing between tabs is, allowing me to see so many so clearly. Also, if you haven't noticed, the developer is uber-responsive and actively engaged in his project, which inspired me to send him a donation right off. This has made FF so much more pleasant and practical to use for me.