If you like high sensi, you'll like to use this app, as it makes the screen faster, to help people who are unable to go up to the cover in the game, or for those who have cell phones that don't have the DPI function (smaller width) .
In addition, FF has less lags, precisely to improve the performance of inferior devices.
Finally, it has a tool that aims to show various configurations that you can test on your Android device, to "up" the gameplay.