I'll agree with "right now," but in the next month or two, Google will be rolling out the pay system for their app market, and that should be pretty appealing to developers. Sure, the base is far smaller right now, but I think the biggest reason I would imagine Android would be more appealing to developers is that there's no arbitrary approval process. As far as I've seen, that has been a horror story for many devs, and many of them don't want to sink a lot of money into an app that they seem to have a 50/50 shot of getting approved. That's how you end up with most of them making money on apps like that stupid iFart.