Firefox
18.0# NEW
- Faster JavaScript performance via IonMonkey compiler
- Support for Retina Display on OS X 10.7 and up
- Preliminary support for WebRTC
# CHANGED
- Experience better image quality with our new HTML scaling algorithm
- Performance improvements around tab switching
# DEVELOPER
- Support for new DOM property window.devicePixelRatio
- Improvement in startup time through smart handling of signed extension certificates
# HTML5
- Support for W3C touch events implemented, taking the place of MozTouch events
# FIXED
- Disable insecure content loading on HTTPS pages
- Improved responsiveness for users on proxies
What can I say? I like this version

Mozilla also updated its mobile version implementing IonMonkey, featuring opt-in search suggestions in the Awesome Bar, including new anti-phising and anti-malware features that warn users when they encounter a malicious website and an integration with the Google Now search widget.
cheers ...