I have spent a solid week really buckling down and using CSHTML5 to implement an actual application.
IT IS AMAZING!!!
I am super impressed with the capabilities even at this beta stage. I created some really capable UI elements and was able to port quite a bit of business logic over with minimal changes.
I was just about to use Xamarin Forms to implement a mobile project but I have decided to scrap that and use CSHTML5 instead. It takes a bit of digging and scratching to find out how to do a few things but as a general proposition my XAML / C# / and Visual Studio skills translated very well and I was able to be productive in very short order.
I am a total fan and can't wait to see where this project goes.