I've had a React Native based fitness tracking app live in both stores for over a year now. If I had to do it over again, I would still choose React Native. It's made the whole cross-platform development process incredibly simple, and it provides excellent tooling out of the box.

Some dependencies on third party libraries made upgrades difficult, but the core library added the functionality I needed eventually, so I no longer run into those issues. Overall it's been pleasant to work with.

iOS app: https://itunes.apple.com/us/app/plansible-weight-lifting-jou...

Android app: https://play.google.com/store/apps/details?id=com.plansible_...