I cleared IBM Portal 399 exam today with 80% marks. I know this is not a great score, but I would take it because I did not have any experience in portal development/RAD etc. I spend 3 weeks preparing for this exam and around 2-3 hours daily.
Let me first thank Java Ranch for helping me in clearing this exam and also Cameron Mckenzie. Cameron has put a great site for portal and his tutorials on portal concept are great. I would strongly suggest every one, who does not have RAD hands on experience, to go through his video tutorials and then take the mock tests.