I can only comment on webOS and android since I haven't yet bought a mac to experiment with iOS. Compared to android webOS is a delight because it uses Javascri

I can only comment on webOS and android since I haven't yet bought a mac to experiment with iOS. Compared to android webOS is a delight because it uses Javascript/HTML/CSS and any web developer can write a webOS app after a few simple tutorials to get acquainted with the APIs. So I'd say the biggest pain point on android is Java because from an architectural standpoint everything these days is MVC and android doesn't deviate from that.