Flight has been under development and review and is slowly nearing a 1.0 release. The documentation is among the few items remaining and will be an essential resource of the final release. Also see Project Status: Flight and Reflex.
Tony Hillerson wrote a framework-comparison series on InsideRIA last year. He built the same twitter client 5 times to offer a thorough evaluation of each framework, a good read if you haven’t yet seen the articles.
Though Flight wasn’t in the public eye at the time, it has finally caught up. Tony hasn’t yet reviewed the framework, but the twitter client known as TwitteRIA is now available as a Flight application. It’s a good example app and nice for comparing Flight with your favorite framework. The source is here.
Enjoy!