[sergiolp]

At flexVDI, we use Xamarin for building our macOS client (Xamarin.Mac), sharing most of the code with the client for Windows, built with Visual Studio. Both of them, link against a shared library which implements core functionality, written in C.

I must say that, having its own quirks and nuisances (specially in Xamarin Studio, which was pretty buggy until version 6.x), it does the job pretty well.

In fact, when we wrote our iOS and Android clients, Xamarin was still pretty immature. But if we had to rewrite them today, it would be one our of first options, right after using the native frameworks (which ensures the best results, but drastically increases the costs).