You had to ask, huh?
On some level, it’s too crude a question to take very seriously. There are just too many ways to define “winning,” and neither platform leads in every area. But here’s the closest thing to an objective answer I can manage: Android, if you’re talking about market share; iOS, if you mean financial success. So far, this is a strikingly different market than the PC business back in the 1990s, when market share translated directly into financial success.