React Native is much slower on Android than on iOS, sometimes by orders of magnitude. You can get things usable on a lower-end Apple device, but on a lower-end Android an optimized RN app is still unusable. Part of this is due to the JS interpreter available on Android (which FB has tried to replace). But I think it's also due to architectural issues in Android itself and the natural overhead that RN has being too much in a constrained environment.