[mythz]

>> Significant compared to what?

Significant, in the fact that there's now a less clear choice of what to use when developing a Windows 8 UI or server application.

>> In my opinion: A strong cross-platform C# eco-system is simply not good for Microsoft.

In that case it's a conflict of interests, as it may not be good for Microsoft, but it's certainly good for the .NET community which lets .NET developers re-use and leverage their work on multiple platforms. Fortunately we have Xamarin filling this void, but if it wasn't for them .NET developers would be missing out on the most exciting mobile platforms to date: iOS / Android.