Of course Android can be beautiful if you showcase a few screen shots created by some very talented designers. After spending the last 4 years as an Android developer, its clear that the platform falls short in two places at the intersection of UX and UI. I've worked with some of the best designers and they always produced beautiful assets and screens, but we were always left making important UX decisions that caused inconsistency with other apps. The "beauty" that many users come to appreciate with iOS and Metro, is the cross app consistency, experience and cohesion with the operating system itself. Even apps produced by Google have a tremendously wide gap in consistency. The other major problem is development decisions made (and allowed by the platform) by software engineers. More than a few of the apps in this list do unthinkable things like processing data on the UI thread or having terrible offline experiences. This can turn a beautifully designed app into a terrible app very quickly.

It's important to distinguish "looks pretty" and "beautiful".