In the webcenter 11g release I noticed that Oracle use taskflows for their webcenter services like document library, worklist etc. I know already that taskflow is very important for the adf and jsf development. But it surprises me that don't create only portlet applications like in the 1o.1.3.2 version. I don't complain about this because I like taskflow more because I don't need the webcenter container to run my portal page. With taskflow I make a specific connection and drag a taskflow from my onw or webcenter catalog. Fill the taskflow mds parameters in and let's run it. If I make a portlet I have to deploy it first to the webcenter container and then I have to make in my portalpage a producer to this portlet and configure it and drag this to the jsf page.
If your company only uses Oracle technology then you should use taskflow and you can always deploy it as a portlet to the webcenter container. The portlet bridge works fine now( PPR and Popup works now) and we can use mds to customize the taskflow. If you want to build portlets because you don't know if you want to use the oc4j container then make sure that you don't use specific oracle technology else you get errors on the other j2ee containers.