Facetime works very well, my family uses it from 4 different continents around the world, from cities to villages, varying from toddlers to nonagenarians who didn't even go to school or know English. I don't know why something cross platform can't work as well as Facetime does.
I had hope for Hangouts, but Google dropped the ball big time in terms of user complexity and quality of product as they are wont to do.