I've been using ReactJS for a long time and thought this would be a good opportunity to try out React Native. I found that I was able to iterate and release on both platforms very quickly with RN. Also, since it's a social network at its core, we wanted to support both platforms from the start to allow for more adoption.
I've come to love React Native. It has been very easy to get started, increase app complexity while keeping code clean and simple, and building the occasional bindings in Obj-C and Java was very straight-forward. I definitely recommend giving RN a shot!