Mono isn't proven anywhere near as much as the JVM.
I don't know why this is being downvoted. It's true that the JVM is one of the things in the Java ecosystem that is looked upon as a massive success.
I don't know why this is being downvoted. It's true that the JVM is one of the things in the Java ecosystem that is looked upon as a massive success.
And it's also true that the CLR really is technically superior to the JVM on a whole slew of points. It has runtime-level support for generics (meaning C# lets you do all sorts of nice things with them that Java doesn't support). It has user-defined value types. It supports coroutines (i.e., 'yield'). It supports anonymous functions and closures. For those who just can't leave pointers alone, it even has unsafe blocks. And so on.
So while it's definitely not "proven" in a sense that will impress your average PHB, in terms of technical merit I don't think there's really any comparison. Mono wins hands-down.
This is kind of tongue in cheek, but seriously... NodeJS is relatively new (since 2009) and it's gained a LOT of traction... it isn't the perfect solution, but then again nothing is. I like Mono and have used it, they've worked through a lot of the earlier issues, and it's pretty decent at this point... IIRC it's the core of the Unity tools, as well as having Xamarin tools available to support the majority of mobile platforms.