Visit the CyanogenMod download page and you'll see CM11 M3 builds are starting to roll off the servers. "M" builds are milestones along the development process as the KitKat-based CyanogenMod 11 approaches release candidate, and eventually stable status. So M-snapshot builds are supposed to be more stable than nightlies, but may still contain a few bugs. At the time of writing we're seeing M3 builds for a wide range of devices including the Galaxy S4, HTC One and LG G2, along with many Nexus devices and legacy handsets. If you're already set up with a custom recovery on your device, you can hit up the source link to find the full list CM11 M3 builds ready for flashing.