>>106851868
>c# is already supported by my visual studio which I already have. other languages don't have good ide support which wastes development time.
Funny, I expressed the same thing as a drawback:
>tightly integrated with a proprietary IDE because it's almost impossible to refactor its extremely rigid classes without one

Other languages don't need as much IDE support and don't tie you down to a single platform. If you are already on Windows and used to Visual Studio then do whatever you like. But this is definitely one of the reasons C# did not get widely adopted.