I see three ways to do the presentation layer stuff for portlets (I am sure there are other ways but these seem to be the ones everyone talks about) Struts, JSF or just using the printwriter of a JSP. What are the advantages of each? What are the disadvantages? What is a good tutorial for learning them? From my first look at Struts and JSF it seems that these make implementation harder not easier.
For a tutorial, the Manning sandbox contains a draft manuscript on portals and portlets by Hepper etal (http://www.manning.com/hepper/). You must register to enter the sandbox but registration is free. It contains examples using plain portlets, portlets with JSPs and JSTL, and portlets with JSF.
See also the discussion at http://www.jboss.com/index.html?module=bb&op=viewtopic&t=88554