Mozilla has finally launched a preview version of Firefox for Windows 8 with a modern UI, which runs in full-screen and is optimized for touch screens. The browser is currently in Aurora development stage. The stable version is expected in January 2014.
It has a tile-based Firefox Start experience and supports Firefox Sync, Windows 8 touch and swipe gestures, Snapped and Fill views, and Windows Share integration all delivered with a streamlined, modern and beautiful interface.
Source: Mozilla