Hi,
the screenshots I've seen of the Dynamic Website Project are showing extJS. ExtJs is available under LGPL, so there is perhaps a question for Alfresco Software as a company and their business model. In my opinion extJs is currently the most powerful ajax framwork if you want to build custom clients. The combination extjs - json - WebScripts - Alfresco Repo seems to be "the road".
I'm not familar with flex…I've seen screenshots of alffrescos new network clients which uses flex. I'm not sure if this is still the plan or if they decided to stay on the AJAX side.
Perhaps you are able to post some screenshots / screencast of your in other topics mentioned flex client. I'm very interested in this flex stuff…
Cheers,
Jan