I did a fair amount of experimentation with phone gap/Cordova a couple of years ago. What really killed me wasn't so much perf as places where you want or need native UI. For example, if you want a nice mapping experience, JS based maps suck on mobile compared to the native map widget.
Based on this I think the Xamarin model makes a lot more sense in today's mobile landscape. Be smart about building shared logic and view controllers and wire it up to fully native UX.
Based on this I think the Xamarin model makes a lot more sense in today's mobile landscape. Be smart about building shared logic and view controllers and wire it up to fully native UX.