This week, in one of the most important government palaces in Italy (I cannot say which one), I did a consultancy about mobile development. The internal dev team is currently using Xamarin and they have a blocking problem with it. In the team there is a friend of mine which called me some days ago to know if I know how to solve their problem using Delphi. I told him that the "blocking" problem could be solved with Delphi. The resultant 2 days of consultancy were been quite hard, but the result has been really rewarding. A long standing problem has been elegantely solved using Delphi in a couple of hours.
The problem was about using HTTP client certificates with iOS in a Microsoft architecture, where each user had its own certificate.
I dont know Xamarine so deeply to say if the problem could be elegantly resolved with it as well, but the team is quite smart and skilled, so I think that they have been tried all the documented solutions to face the problem, but without success.