Additionally, the libraries and tools built by the broader React community are available for use in ReactVR.
What about performance? From the announcement:
As it turns out, React Native already addresses similar problems with its architecture. We followed RN's pattern by running React and rendering in separate contexts, with an asynchronous bridge for communication between them. In the web browser, this separation is performed with a web worker—your entire React application runs in the worker, while the rendering code that turns scene update messages into actual pixels lives in the main window. This lets the renderer create a tight loop between receiving headset orientation updates and re-rendering the scene, increasing viewer immersion while decreasing the likelihood of motion-sickness.