When you use .NET to target iOS, you still use all the iOS frameworks. It's not like those cross platform Java widgets. The only thing that changes is that you

When you use .NET to target iOS, you still use all the iOS frameworks. It's not like those cross platform Java widgets. The only thing that changes is that you don't need to use ObjC or Swift. Yes you have another stdlib, but your main investment in learning the UI and other platform specific stuff is not lost. F# really is so much better, too. And C# is pretty great if you haven't embraced the holy lambda yet.