Anecdotally we've got a RN app, and we've only got one or two native source files for each platform, which are mostly there to bridge in third-party libraries for things like analytics. Our UI and business logic are almost 100% JS and it works out really nicely for us
Of course this is a mostly standard (but not small) CRUD app. We've got some custom animations/widgets here and there, but mostly it's vanilla forms, controls, views, etc. which translate easily to both platforms
We also started out on RN from the beginning; it's possible that migrating to it from native code is a much bigger challenge
Same for us. Certain dev environments bugs were been a big pain in the ass for us in the past. For the logic side of thing React Native has been a nice experience for us as well!
Of course this is a mostly standard (but not small) CRUD app. We've got some custom animations/widgets here and there, but mostly it's vanilla forms, controls, views, etc. which translate easily to both platforms
We also started out on RN from the beginning; it's possible that migrating to it from native code is a much bigger challenge