At Enyosolutions, we have almost as many React Native apps as Ionic apps. And in our experience, the technologies are not intended for the same projects.
While Ionic is easier to learn and faster to build, React Native apps allow a lot more functionality and better performance. The choice of technology will therefore play a major role in the UX of the application.
React Native will also be more stable and robust over time (less bugs due to the application itself), but will require more maintenance. Compiling and debugging is much more difficult because it is mandatory to go through iOS and Android emulators to test the implementations.
The ecosystem and APIs are also very much alive, which is a good thing to be at the cutting edge of technology and up to date in terms of security. On the other hand, there may be compilation problems which make it difficult to update applications.
Key is the anticipation, indeed, if your staff feels conformtable with Angular and web technologies select Ionic. More and more Wed Developers feel more comfortable with ReactJS, in this case, select React Native.