I managed to get a great score today, got only 3 questions wrong.
A big thanks to the HFEJB book and the approach! Using this book as the primary study source provided a good coverage of the exam objectives. The mock exam in the book was really hard and I only got about 77% correctly on the evening before the exam.
To me the actual exam was a lot easier, just because I did not have to guess how many questions are correct. The observation that I have made: If you are prepared to take the test the Head-First way, you will have a great feeling while taking the real exam.
As not all the details can be found in this book, I had to look some things up in the EJB spec. Thanks to Kathy and Bert, I did not need to read the whole spec, which saved me great amount of time. I have spent 10 man days preparing for the exam and have had about 2.5 years prior active EJB programming experience.