William Drai has blogged about his experience integrating Granite DS and CDI.
Our feeling is that JCDI is a perfect fit for Flex RIAs with an event-driven architecture. JCDI applications look extremely clean and even though JBoss Seam provides a lot more features, they do not necessarily make sense with a RIA front-end.
The mapping to Flex does look very clean to me. I especially like what William has done with mapping CDI events into the client. Very nice, and very faithful to CDI.