I've read/watched most of your blog/tuts and it seems you are the "beautiful front-ends for Java based back-ends" guru ;) That (sucking up ;) said, I want to build a highly scalable "facebook for business" and after much testing am pretty set on FlashBuilder4 (Flex) with Google App Engine (GAE). What are your thoughts on the need/advisability of also using Spring/Cairngorm/etc frameworks? Frankly I don't have extensive experience coding, however feel the "MVC utopia" universally aspired to becomes convoluting when duplicating between front and back ends as envisioned above (i.e. Flex/ActionScript and GAE/Java respectively).