Why use firefox for web development? Chrome/Safari's Web Inspector is infinitely better than Firefox's extension dev tools. I've used the Safari ones for years and find them significantly better, easier to find details about elements. Easier to debug script. Just so much time saved.
would browser profiles really be that hard. Chrome has the User-switcher in the top left (right in osx) as a giant icon. If you're in the wrong profile.. you can just click the icon.. new window with the right profile loaded. idiot-proof really.