From James Long's blog post:
The ability to declaratively construct my UI as components and respond to events by simply changing state is powerful. React.js has proven that. Suddenly, we get to do the exact same thing for native apps. "Learn once, write anywhere" as the React devs say.
I have mixed feelings about React Native. I know it is a big deal, and a lot of people (including myself) are intrigued by it. But I'll just wait to try it, maybe I'll like it, maybe not.