Rated 3 out of 5 stars
While I do like this extension, and am grateful for your hard work, it currently has a conflict with custom toolbars, when they are created via toolbar Customize > Add New Toolbar. Any toolbar created is completely "forgotten" when the browser is restarted. Disabling the Hackbar extension resolves the issue.
My environment is Ubuntu 11.10 + Firefox 10.0.2.
Thanks for all you have done to create this extension, and the best of luck with it. :)