Rate Windows 8 touch usability

How would you rate Windows 8 touch usability compared with iOS and Stock Android, and to an extent multi touch gestures on OS X?

I actually find Android's touch gestures making more sense to me than iOS ie option of swiping left or right on the multi-tasking screen to close an app instead of swiping up only on iOS. On Windows 8 metro, you have to be in that app to close it or you can use the keyboard shortcuts.

But that is once example, and the keyboard is there to augment somewhat certain touch usability - but what if we are talking strictly using touch only - what do you think of Microsoft's implementation of the touch interface?