The exam is definitely not a monster exam. After taking the exam I believe that you dont have to be an expert to clear the test. I took the test without actually "working" with XML at all.
- Lot of the questions were concerning what one would use (XSLT or CSS, DOM or SAX, etc...) in a given scenario. So it would be definitely be a good idea to understand the pros/cons of each approach.
- Quite a few questions of schema (The 2 Schema related chapters in Wrox's "Beginner XML" was sufficient; at least for the questions that I got).
- Would be good if you knew the functions that are available in XSLT (Appendix of book titled "XSLT" by Doug Tidwell, Publishers
- Some very basic questions on Namespaces, DOM and SAX.
- There were a few questions on Information Modelling that I had no idea what they were talking about.
- Couple of questions on XML Security and interaction of XML with databases.
Hope the above helps.