I will definitely be giving it a try as soon as I can. Right now you can't easily go from React Native to web and you can't be 100% certain that mobile apps written in React Native will always work on Android and iOS because some RN APIs are only implemented for either platform. With ReactXP, they only expose the RN APIs that are common to both platforms, which gives a much higher confidence level for true cross platform reuse of app code.

This looks really interesting; I'm looking forward to seeing production adoption of ReactXP.

No problem! Implicity any fefinitely makes TS much more usable in comparison to Flow, and with the significantly larger community and better tooling, TS is a no brainer against Flow.

j in what way are 3rd party libraries tricky to integrate? In older versions of TS you would need to install typings from DefinitelyTyped like you said, but as of TypeScript 2.1, you can know use any 3rd party JS libraries as you would without TS because of the new default implicityAny option in the tsconfig.json. Of course, it would be ideal to have type definitions for your code and any libraries you're using in order to get the most out of TypeScript during development; but this is no longer a requirement.