This article does a good job of talking about how poor the windows experience on a handheld is, and why SteamOS could dominate handheld devices if windows doesn't start to make serious changes to improve it's useability and performance.

To be clear, I don't want to see windows succeed here, I would absolutely love to see SteamOS take over the handheld space and be a real linux ambassador to show people that they do have other choices than windows for their computers.