I am giving a talk at the New England Java Users Group in the near future on portability of EJB 1.1 code. I have had some experience with this with WebLogic and JBoss but I very interested to hear other peoples experiences
and thoughts on the subject.

What are the main points of 'friction' when porting between App Servers? What did you do to get past them and what would you do design wise to make porting easier in the future?