Xamarin and Calatrava

While there have been scores of tools in the market in the space of cross monile development platforms, i have always liked Xamarin due to its obvious affinity with c#...read an interesting take on cons of Xamarin at
http://www.whitneyland.com/2013/05/why-i-dont-recommend-xamarin-for-mobile-development.html

Also one of the tools the folks mention is Calatrava, a good tool built with support from Thoughtworks.

http://calatrava.github.io