There aren't a ton of devices running the commercial Cyanogen OS ROM these days, but the Wileyfox Spark and Spark+ are two of the most prominent (which really tells you something). These UK phones launched with Cyanogen OS 12 (Lollipop) earlier this year, but now Cyanogen OS 13 is finally rolling out.
Cyanogen OS 13 is based on Marshmallow, so you get all the core features of that update including doze mode, improved permission management, and Google Now on Tap. In addition, the Cyanogen build of Marshmallow includes revamped quick settings customization and Truecaller caller ID.
The Wileyfox Spark and Spark+ are not particularly speedy phones, but they retail for a mere £89.99 (about $120) and £114.99 (about $150), respectively. The post from Cyanogen Inc. just says that the update is rolling out. We don't know if it's staged or not.