I don't really understand RxJS that well, but here is where my understanding is at. RxJS helps with composition and dataloading. On a theorectical level, isn't it ideal to have Redux used with RxJS? How do you do global state management with RxJS?
I haven't come across a project using only React and RxJS though. There is redux-observable [1] if you haven't seen yet that combines Redux and RxJS.
[0]: http://redux.js.org/docs/introduction/PriorArt.html#rxjs