● Retina Display Support: Firefox Beta supports Retina Display for Mac users to make Firefox even sharper when watching movies, playing games and browsing the Web.
● Disable Insecure Content: Firefox Beta can disable insecure content on HTTPS secure websites to maintain the privacy of your communication with the website. You can enable the feature in about:config.
● Support for W3C Touch Events: Firefox Beta supports standard W3C touch events in addition to MozTouch events.
You can get the beta from the link below...