Hello Yesterday I took my SCWCD exam I passed with 91% I found if you read the Head First book is good enough to get around 70% but you really need to take a look into specs specially for the DD elements and check the JSP spec for the Standard Actions, EL and custom tags. If you do this you shoul get around 80%. Also I think it is a must download tomcat and do as much exemples as possible specially checking the JSP translated code for standar actions. This should make it for the 90%. Above that I think you need to be lucky or have a lot of experience in servlet and jsp.
But it was a great experience because beside servlet and jsp I revisit my basic concepts of java like, threads, collections, etc.. Reviewing the specification I learned more about xml schemas and xml namespaces I learned about patterns I am sure this will help me to see my programatic problems from different inshights. So beside the number there are a lot of hidden values when taking the exam.
Actually I must say without the Head First book I had not got such score I think the book gave me a very good understanding of the concetps then I had to sharpen this with additional material. Cogratulation to Bert, Katy and Bryan to write such a great and didactical book.