I haven't had the time to play with Telerik's NativeScript yet and I was thinking it was something similar to Cordova where the app is coded in HTML/JavaScript and rendered in a web view.  Boy was I wrong!  What shed a light on this was Telerik's Burke Holland's NativeScript And Xamarin article that does a fairly good job at comparing both technologies considering that NativeScript is a Telerik technology (Telerik also has a Xamarin controls suite).