If you know React, find React's declarative style of programming desirable, or have a more complex, stateful application, then React VR is your best bet. It's true that the A-Frame community is larger than the React VR community, and there's more code out there for it, but React VR integrates with the entire history of React tooling and libraries – React VR doesn't need a specific data management or navigation library, because it's just React. Our goal is to take all web developers who know React and enable them to become VR developers as well.