If you want to look at it in simple terms then yes it's not easy to say what carriers vs wifi work best. The main reason for this is no adult setups for carriers to bill our style of content so it's all non adult like games, consumables etc.
If you really look closely at your traffic and can find a partner that is willing to stand out from the crowd and tell you what carrier in the US, what OS in the US works best on your traffic on what product then you will see a definable diferential that will allow you to earn more from your traffic IMO
