Our team threw this together in a couple weekends when we were test driving react native: https://itunes.apple.com/us/app/emergency-kittens-adorable/i...

The ability to reuse code is very real, even sharing a lot with a web react app since most state/business logic is in some flux implementation.

The pain points (documentation, build process, etc.) are real, too, but things I can forgive for now due to its newness and its very strong foundation.