While I can’t speak towards development in swift, I can confidently say that react native is incredible. With the flexibility of npm packages and the ability to share code between your Android and iOS builds, it can allow a small development team to pump out quality applications very quickly.
That being said, it’s not perfect. Things like hot code reloads make development a breeze, but when you start hitting the deployment stages ( or anytime you need to manage / update native code ) it can become extremely challenging.
React native is continuing to grow quickly and enables you to move fast while still retaining a lot of the benefits of native development.
Overall react native has my vote