Mono works really well. But, Mono's not the future. The future is Roslyn, CoreCLR, and CoreFX, basically the compiler, runtime and standard library for .NET app

Mono works really well. But, Mono's not the future. The future is Roslyn, CoreCLR, and CoreFX, basically the compiler, runtime and standard library for .NET applications. They all work really well on Linux. They're part of the .NET foundation (https://github.com/dotnet https://github.com/dotnet).