Marco didn't hit the target here: beyond the risk to be an attractive platform from the point of view of the developer the speed of development in Visual Studio /.NET is superior than Eclipsr/XCode. Beyond average developers will feel comfortable with their platform of choice but below average developers can go to market very fast
I've been transitioning from Visual Studio/.NET/WPF/Resharper to Xcode/Vim this past month. While I feel like the microsoft programming environment is way more productive, at the end of the day an I care less about the development environment, and more about whether what I'm making will have an impact and make money.
I'm expecting many developers that long for a better dev. environment to buy 3rd party IDE's like IntelliJ IDEA & AppCode. They also cost less than what you'd spend on Visual Studio Professional (yes, i know i'm ignoring bizspark here).
Along with this, I'm just not excited about microsoft's pitch with surface as a laptop replacement. I want a tablet that replaces books and paper. Those aspects still require hardware design that feels good in "vertical" mode.
Your comment relates to the risk of developing for a platform without an interesting market. That is true and time will say how much market can Microsoft win in the mobile space.
If Microsoft increases their market share significantly, then "everyone" could go to market very fast with Visual Studio. In my opinion they will achieve significant success in less than 2 years.
