Linux Mint is an Ubuntu-based distribution whose goal is to provide a more complete out-of-the-box experience by including browser plugins, media codecs, support for DVD playback, Java and other components. It also adds a custom desktop and menus, several unique configuration tools, and a web-based package installation interface. Linux Mint is compatible with Ubuntu software repositories.
Please note this is not the "RC" version, this is the official release edition of Mint 15 XFCE, the release version was made available to the public on July 12th, 2013.
http://blog.linuxmint.com/?p=2391