My voucher is expiring this month and i had to do it. This is the way I force myself to do certifications!
I have been working on an EJB3/JPA project since 2 years and that was(as i had hoped) really helpful. The materials i used:
- EJB3 in Action - Terrific book. This is what i use in my day-to-day reference in project as well. So i even knew which topic was in which page.
- Enthuware - This gives you a very good orientation of the exam and forces you learn exam specific topics. For example, I have never used a Stateful session bean in my life. But hey now i know atleast in theory! IMO enthuware is almost a 'SCJP study guide by Kathy Sierra' for SCBCD. The questions are tougher than the real exam though.
Good luck to you folks. I am thinking about Spring certification next.