First of all the damn good news is that OnePlus One gets OFFICIAL CyanogenMod 13.0 NIGHTLY release. You can visit our forum link for the official CM 13 OPO release.
As you all know that Android Marshmallow source code has been released since a couple of months from now and there are also some UNOFFICIAL CyanogenMod builds released by different developers for different devices. Now it starts with OnePlus One that it goes official and soon you will also see some official CM releases for other devices.
Official vs Unofficial CyanogenMod release:
The OFFICIAL releases come everyday and the developers at CyanogenMod review all the changes before approving a change. So the official CyanogenMod releases will definitely be the best among all the CyanogenMod ROMs out there.
On the other hand the unofficial releases are made by individual developers. The releases may come after a month. Meaning you have to live with a bug for months.
As there are no review on the code, that means there may not be stable code for a particular release.
Cyanogen OS vs CyanogenMod:
One more important point for the OnePlus One users is: this is not a Cyanogen OS release. This is CyanogenMod.
CyanogenMod releases are made by developers like you and me. But the Cyanogen OS is the commercial version which will undergo Google’s test suite certification and contains extra optimizations over CyanogenMod.
CyanogenMod features same across devices. Meaning, a CyanogenMod on Moto X and another on OnePlus One will not have any differences on feature set.
On the other hand Cyanogen OS for OnePlus One will have some extra optimizations and added features over CyanogenMod for OPO, where there will be no Cyanogen OS for Moto X.
Only those devices will get Cyanogen OS which have exclusive tie-up with Cyanogen team.