If you'd like to try this out on Windows without affecting your main Firefox profile, we just released portable packages of the Firefox Nightly and Aurora build

If you'd like to try this out on Windows without affecting your main Firefox profile, we just released portable packages of the Firefox Nightly and Aurora builds at PortableApps.com yesterday: http://portableapps.com/news/2013-12-04--firefox-aurora-27-and-nightly-28-portable-released http://portableapps.com/news/2013-12-04--firefox-aurora-27-a... They run self-contained in their own directory so you can quickly extract them to your Desktop or portable device. The installer downloads the latest build as you install it and configures it for standalone use. When you're done testing, you can just delete the FirefoxPortableNightly directory. Bonus: The Nightly branch also has the new Australis UI redesign that they've been working on and is worth checking out.