This article hits close to home. I've been working with Xamarin for almost two years now. It has done its job and provided a quick avenue to prototype a concept and deliver a product. However, as the article mentions, the maintenance is a bear. Here are some of the issues I face:

- The developer experience is awful. Visual Studio for Mac causes so many issues (crashes, mangled project files) it hinders productivity. About once every two weeks I spend half a day wrestling with a VS issue.

- As AirBnB's article mentioned, to be effective in cross-platform development, you need to know three platforms well which is a difficult task.

- Xamarin's performance on Android has notoriously been poor and only has marginally improved. Try using a Xamarin app on a cheaper Android device or an older version of Android.

- No mobile engineers want to work on Xamarin.

That said, the good news about working with Xamarin is that it exposed me to C# and the .NET ecosystem. I'm truly impressed with these technologies.

EDIT

I forgot to mention that I think the complexity of an app ought to determine whether a cross-platform technology is a good idea. Xamarin is a great solution for prototypes and simple apps.