So you're a fan of custom ROMs, but you're not quite ready to live on the bleeding edge (or alternately, your device doesn't have a reliable Android 4.3 build yet). Fear not, cautious Android power user: the CyanogenMod team has a build for you! CyanogenMod 10.1.3 will be the last version of CM based on Android 4.2, and release candidates are now being posted for supported phones and tablets.
10.1.3 is more precisely based on Android 4.2.2, with all the bells and whistles that Google and CyanogenMod could shove into last year's release. According to this CyanogenMod blog post, 10.1.3 also includes a few last-minute goodies like Privacy Guard and SELinux, which were previously restricted to nightly builds. Speaking of which, a Release Candidate is exactly what it sounds like: a nearly-finished build that the creators think could be ready for general release. They tend to be much more reliable than nightlies. At this point, it might be more prudent to wait for a Stable (final) build after another one or two more candidates, but you probably won't find any horrendous bugs in RC1.
If you've jumped the gun and already installed one of the CyanogenMod 10.2 (Android 4.3) nightly builds on your device, you'll need to do a complete wipe if you want to return to 10.1 for the release candidate. And as always, you'll need the correct Gapps ZIP file if you want access to the Play Store and Google services. A Nandroid backup wouldn't go amiss either. At the time of writing ten device builds have been posted to Get.CM, and the rest should be finished sometime tonight or tomorrow morning. Remember that the build boxes publish in alphabetical order of codename.
Source: CyanogenMod blog