I’ve had this plugin installed for about 2 weeks and it’s just great.
Essentially, the extension removes the menu bar from Firefox. This was one of my last pet peeves about Firefox since I was used to IE’s ability to elminate the menu portion. In Firefox, you can’t do that. So, with this extension, the menu bar goes away and you can then modify the other toolbars to fit your liking. I think I have it down to just about the minimum I need and its nice and clean.