Can anyone compare this to Xamarin in terms of features/stability/workflow ? Xamarin is .NET/C# which is arguably nicer than Java but its also not too cheap if you just want to play around with stuff.
Anyway I'm happy to see competion against xamarin. Now I only want also a javascript to native (and not just webview-running) for any platform
As for a JavaScript to native compiler, check out Appcelerator Hyperloop [1]. It's currently experimental.
If you just want to play around then take note that the starter plans are free [1].