I'm a beginner, but I decided to go with Silverlight 5 while using this book. I started by grabbing a template from Microsoft and then adding in chunks and bits from this book to my personalized solution. So my solution mirrors the book, but with a whole different set of template xaml styles. I'm currently almost finished with Chapter 4 and will likely begin my departure from fitnesstrackerplus features to the features my website requires.
If anyone has any requests for how this looks from a Silverlight 5 perspective, I'll try to answer with code examples.