I believe it really depends on what you've done in your game.

Here, we made an application for iOS and it was running without any modification on Android.

The main problem we met : it's easy to test performances on iOS because there are only a few different devices. But there are a lot of different Android devices, and there are on average less powerfull as iOS devices.

In our case, our game wasn't running as smoothly on most Android devices that it did on iOS devices.