It's getting close to another six-month update for the Ubuntu-based Linux Mint and the big feature this time around is the Cinnamon 2.0 desktop.
Linux Mint 16 has Cinnamon 2.0 plus the MDM 1.4 log-in screen, USB stick improvements, performance improvements, software manager improvements, and various system improvements. Some of the system work in Linux Mint 16 include safer kernel upgrades, a faster boot sequence, better EFI support, improved support for iOS devices, better Steam support, APT improvements, and various other changes throughout the stack.
Some of the performance work for Linux Mint 16 includes boot/login improvements, the MDM display manager no longer deals with the network, the update manager is now started after a delay, significant speed improvements to the Software Manager, and the Linux Mint 16 ISO images are no longer compressed to make starting up live sessions faster.
More details on the Linux Mint 16 Release Candidate can be found via the Mint blog post and the new features page.