We went back to C++ because C# just isn't supported on Linux well, and Windows is losing its once dominant position. If C# worked on iOS and Linux equivalently to Windows, then I probably would have stuck with it.
But now I do JavaScript + WebGL (which is admittedly slower than both C#, Java and C++): http://clara.io
https://xamarin.com/ imho a much better alternative to C++. I really like C# as a language, it's got that general purpose excellence, but when you get on with things like LINQ,Rx,TPL it's very hard to go back to a language without such first class citizen frameworks.
But now I do JavaScript + WebGL (which is admittedly slower than both C#, Java and C++): http://clara.io