Over the past 9 months my colleagues and I have been developing an enterprise portal using JBoss Portal and Alfresco.  Currently, Alfresco does not offer out of the box content portlets so we created our own.  Working closely with Alfresco we chose to use their new WCM product for its user sandbox and workflow approval features.  This article explains some interesting findings related to performance and scalability when integrating with Alfresco web content.