For Gaming ? Obviously Android.
There are so much more games in Android ( including the ones that are unverified and might contain virus, but whatever ) than in iOS. Android is just so customizable that you can change the way things works to your own likings, making it easier to do things, including Gaming. You can also easily get high-quality games that are supposed to be a paid game, for free! illegally. You can even modify a game and cheat your way through also illegally, and all without having to root, not like iOS where you have to jailbreak to do anything mentioned.