Now that Firefox has multi-process support, is it as secure as Chrome (or Chromium) now? Privacy wise, is Firefox still the leader? Having run Chromium on Ubuntu and Dragon on Windows, I am now looking to use one or the other on these platforms. All advice welcome ;D.
The sandbox in Firefox in not done yet, particularly on Windows, so it is currently not as secure (restricted) as Chromium. See details in the wiki: https://wiki.mozilla.org/Security/Sandbox
Privacy is hard to compare, because it depends on your settings and extensions.