Rated 5 out of 5 stars
This is an incredibly useful addon - especially if you have a Netbook and screen real estate is at a premium - and it now works for both Ffox and Tbird (3.x)!
The developer is incredibly responsive to bug reports and feature requests. The Auto-Hide feature now works about as reliably as the Windows Taskbar Auto-Hide - meaning, virtually always works as expected, every now and then kind of forgets which state it is in, but a quick mouse-over of the hotspost fixes that right up.
With the recent changes/fixes - hotspot changed to the Window Title Bar, and the annoyance of the Menu Bar auto hiding itself while you are typing in the Awesome bar (or the Tbird Search box) - this is now one of my favorite and must have extensions.