|Pocket Legends is a pretty cool MMO.|
Here's the interesting part: Android users generate 30% to 50% more revenue per day from in-app purchases than iOS users, despite the fact that in-app purchasing on Android is a jury-rigged affair right now. (Google will debut built-in in-app purchasing for Android this May.) Even more interesting, Android users click on ads at three times the rate that iOS users do (Spacetime also uses ads to generate revenue).
I'm not sure why they are doing so much better on Android; perhaps it has to do with their marketing efforts. It's an interesting object lesson that you can't always predict revenue for a platform purely by the number of users or unit sales of hardware.