Neat. A huge amount of de-clutter power. Rated 5 out of 5 stars
I run 3.5.6 with (among lots of other add-ons) 'Tiny Menu' and a toolbar button to 'Toggle the Bookmark Toolbar.' This newbie interacts very well with those, which I thought would conflict.
One thing I'd like added: Hide Menubar's very own toolbar button that would mimic the action of pressing Alt.