Hides the title bar perfectly well but... Rated 2 out of 5 stars
Maximize is botched - expands the window to a 1260 by 918px rectangle hitched to the top-left corner of my 1400 by 1050 screen. This alone, as you can imagine, makes it unusable for me. Alt-space+R to restore the window size (unmaximize) doesn't work either.
Would be nice if you could double-click toolbars or statusbar to replicate the double-clicking-titlebar behaviour. Also, personally, I'd rather not have to install the Tiny Menu which, annoyingly, immediately makes itself at home, so to speak. I use the Personal Menu add-on and am quite happy with it.
Am using FF3.6 on WinXP. Will try this add-on again at a later date to see if resizing issues have been fixed, in which case I'd likely re-review. In the mean time, can't use nor recommend.