GitHub User: urbanautomaton
Glad to see this - we've started using Draper at Tribesports recently, and we're really happy with it. We wrote a couple of blog posts on how it can help implement a clean, versioned API, if anyone's interested:
Part 1 - Versioning the Tribesports API
Part 2 - Separating API logic with decorators
We're actually using it in combination with Cells (mentioned above); we think they're highly complementary. Our site makes heavy use of small resource-specific elements repeated in multiple contexts. Cells lets us pick out the resources we're displaying in a structured manner (cleaning up our controllers), and draper handles the decoration, cleaning up the views.