Free for licensing, it's 100% compatible with all Android apps (over 1.5 million apps...)
Source:
http://www.jide.com/en/remixos-for-pc
Forum:What is Remix OS?
Remix OS is our state of the art Android-based operating system. We mean it when we say you get a PC experience unlike anything on Android and an Android experience unlike anything on a PC. The innovative features we’ve brought to Remix OS 2.0 have been meticulously engineered to bring you the best of both worlds – the harmonious fusion of a mobile and desktop experience.
http://forum.xda-developers.com/remix
Remix OS from Jide is a reimagination of Android that provides a desktop-like windowed environment, powered by Android, to grant the benefits of the mobile OS with productivity characteristics of a desktop operating system such as a taskbar, true multi-tasking, and more. It's currently available on hardware made by Jide, such as the Remix Mini, but is also available as a bootable operating system for X86 devices.