Chartboost: iPhone accounts for 61 percent of overall mobile gaming among iOS devices
iPhone has five-times more gameplay sessions than the iPod Touch, which is at 11 percent. iPad equates to 28 percent of user gameplay among the family of iOS devices.
Advertisement-wise, iPad users are more than twice (113 percent) as likely as iPhone users to download a game after seeing an interstitial for it. iPod Touch users are 85 percent more likely.
Chartboost noted that although the majority of users play games on their iOS smartphone, mobile game developers should know that there are users that can be acquired on the cheap on iPad and iPod Touch. Both iPad and iPod Touch have a $1.68 cost per install (CPI) rate compared to iPhone at $1.80.