I haven't studied for SCBCD or SCDJWS - I did look at the objectives for each, but thought they looked really quite dry. And there is always a debate about the
EJB tier of the platform being too bloated (which is becoming less true as things are starting to simplify with more standardisation in newer releases of
Java EE). Really which you take is a matter of priorities. I am tempted to say that SCWCD is more useful to do before SCDJWS as you'll probably find yourself deploying Web services alongside other Web components, but you may not - it all depends! SCBCD can be done pretty much any time you like.
If I were to choose just one of these certification programmes to sit, it'd be SCWCD (obviously, else I wouldn't be here promoting it!!), for the reason that it's more interesting and lets me show my work off more to colleagues and other clients. Plus EJBs are usually overkill for the sorts of Java EE projects I work on, where a combination of POJOs and JPA often suffices.
Charles Lyons (SCJP 1.4, April 2003; SCJP 5, Dec 2006; SCWCD 1.4b, April 2004)
Author of OCEJWCD Study Companion for Oracle Exam 1Z0-899 (ISBN 0955160340 / Amazon Amazon UK )