XAML is more preferred for WPF application. Which support data binding concept very well.
xaml is better
Xaml is Better when compared to HTML5. *Data Binding by using Xaml *Setting Styles *It is relevant code for windows 10(Mobile and Desktop)
http://programmers.stackexchange.com/questions/156361/advantages-and-disadvantages-to-using-xaml-c-or-html5-javascipt-for-metro-apps