High performance UI without compromises
This feature is especially dear to me. Its one of the handful of things I had in the first deck outlining what the new XAML platform in Windows 8 was going to be. We spent the couple months preceding the release of the Developer Preview working on a brand new graphics stack with independent animation support, and it was only once that was in place that we could expose the niceties of this interop feature set.
Together with our web interop story, surfaced via the WebView control, the XAML-DX interop feature set represents our beliefs that app developers shouldn't have to pick between reuse and new code, nor between high performance and high productivity. Your feedback is appreciated.