I like React and React Native, but the latter hits me as not being the best choice form mobile development, especially for a small team: imagine you are developing an app for Android and iOS in React Native, you got your Android developer and your iOS developer learn React, they start implementing, they stumble upon a roadblock and need to dive deeper in the platform to solve; it's alright they were doing Native before, they can handle it, but soon, as they need to focus on being more experienced in React, they might feel less comfortable with evolving best practices in the underlying platform. Now you need to keep up to date in the native platform and in React.

I wish react native the best and I am going to use it some times (it has lots of perfect use cases in simpler apps, in my opinion), but for more involved projects, I would still choose Java/Swift (and how about a react style framework in the native frameworks?) :)