Is there any reason these browsers would be more functional than regular Firefox with Sideberry or the Tree Style Tabs extensions?
I use Sideberry at work and at home. Between the containers, folder sorting, tab sleeping, and snapshots, I haven't found another browser configuration that's as flexible and functional.
Not to mention it works with any release or flavor of Firefox. So I don't have to worry about weird issues with non-standard browsers.
*Bonus points if you take the 10 minutes to setup a stylesheet to hide the default horizontal tabs.