, ZippyV wrote

IMO, people who want to use html to create an application should use the w3 standards and stay away from WinJS. If they want to create a real applications for Windows they should use .net or C++.

++ x 10
Use "WinJS" when it makes sense, but not all over your app (ie. use standard web technologies whenever possible). Keep the Windows specific calls in modules away from your core logic. This will keep your app mostly portable.