If I am working on C++ and I need net programming using either Java or C# ( to get rid of C++ complexity - the one and only one reason I would switch to JAva or C# ), then my preference would go for C#. The obvious reason is I dont want to learn one more programming envioronment ( Sun ) while I am using Visual Studio (.NET) . But if somebody is already using Java then I don't see any point him to moving towards C#.