Smithjoara

We’re using Rails and a React Native app, but we’re considering using RubyMotion or Emberjs for the next version.
This is one of those questions where it depends on what kind of technology you have available to you, but generally speaking, we would suggest that if you are building your own technology stack and you want to do cross-platform mobile development, then RubyMotion is probably a better choice.
If however you are looking at a platform that already has a lot of cross-platform support because it is open source at its core (like iOS), then Emberjs would be a good choice. This is definitely not the case for every case — there are many situations where native frameworks like React Native or WebGL work better than Rails in certain circumstances. (For example, if your app runs on multiple platforms and needs to do incremental device updates). But if you don't use native apps so much, Rails may be the right choice for your project due to its simplicity and ease of use.