I have been working with Joomla for a long time, but of late have been focusing on Nooku. Not that I don't think that the moves made in Joomla! 1.6+ and beyond are great (especially the RESTFul implmentation in the Application folder of the framework), but am enjoying using Nooku for its Service Oriented Attributes (check out Engineering Internals of a RAD Framework... as a PHP Developer which I just wrote as the second post for the TopTal blog)