Passed yesterday with 85% Here's how I prepared for it:
Started of with Whizlabs (before I saw other comments in this forum). Used their training video and exam simulator. The Whizlabs products I used are very poor quality. Lots of mistakes, very poor English and questions that are difficult to understand (and did I mention innacurate?). Their wesite can also be very slow at times which is very frustrating. I would not recommend Whizlabs at all - very poor.
I then read the Servlet 3 Spec. Useful, although very dull compared with Head First
I then started using the Enthuware exam simulator. It was GREAT!. Really helps test your knowledge. Also has some questions which I would never had known the answer to if I hadn't used the simulator (e.g. do you know what the possible values returned by Enum ServletSecurity.TransportGuarantee are?) I completed all the exams getting 68%, 75%, 75% for the last 3 exams and 68% for the final one. I then used Enthuwares Leitner mode to answer all questions to at least level 1 (with more than 200 to level 2). This took a lot of work but was worth it.
The Enthuware software/exam questions were great and really helped me pass.
If you're taking the exam soon then good luck. Prepare with Head First and Enthuware and you'll do fine