According to this link its a muddled picture but it looks like the most downloaded apps are Android whereas Apple still makes more money from apps. This could be just being entrenched and charging more for the apps plus forcing more in app purchases to get the functionality originally perceived.
Who’s Winning, iOS or Android? All the Numbers, All in One Place | TIME.com
A comprehensive look at the competitive situation, from unit sales to profit margins.
Anyway I’m a PC and IPad user. I think developers would be foolish not to exploit the Android market as Apple continues its over priced/under spec’d policy. I really like my IPad but things like no usb is just a sad joke.