After the long drawn out saga in India which resulted in a temporary ban on OnePlus from selling the OnePlus One in India due to a complaint from Micromax over the use of CyanogenMod, OnePlus has released the Alpha build of its own new ROM. OnePlus had promised the users of India that it would be making available a brand new ROM flashable via an OTA after CyanogenMod had withdrawn any future support from the device in the country.
The first build of the independent ROM is basically an AOSP ROM with absolutely no customizations from the OEM. It is basically as Nexus as Nexus would be. While this is obviously not the final build and far from ready for everyday use, the ROM is definitely a peek into the future plans that OnePlus is planning. The ROM currently is on Android 5.0 Lollipop.
The major differentiator for OnePlus One has been its high-end specifications, low price point as well as the customizations possible thanks to CyanogenMod. With the new ROM largely AOSP, a major part of the differentiation is gone, but you would hope that by the time the final build is released, the ROM would bring some new interesting features which would differentiate it from a Nexus experience. The ROM is flashable via TWRP but has major drawbacks such as issues with camera and problems with capacitive and on-screen buttons. You can find the ROM and download the same from the XDA thread here.