Firefox is never going to lose me as a user as long as the awesome Tree-style tabs extension - https://addons.mozilla.org/en-US/firefox/addon/tree-style-ta...

is supported on it. It completely changed my browsing experience, and I cannot use any other browser except for quick, temporary browsing (like how one might use Notepad on Windows in a bind).

I'd highly, highly recommend this extension to anyone who has never had the pleasure to use it.