Just passed my SCEA part 1 today with a score of 70%! Not sure I wholly deserved it... I hold a PhD in high-energy physics so I think I've seen my share of difficult exams -- this is a difficult exam, people.
Looking back I made the mistake, somewhat naively, that if you know the Study Guide inside out, you're there. I did read my share of other books, so I sort of got lucky that I had enough background. The "100% coverage" on the cover of the Study Guide is a total joke and misleading.
I was definitely lacking background on Java Messaging, which I have on the shelf here but haven't had time to read yet. Looking at the section titles, I think you need to read this book unless you think you're lucky like I was. The exam also asked several questions about JEEpatterns, which mentioned Study Guide says it NOT part of it. And finally I was missing background on Java Server Faces -- I only have experience with Struts.
Finally -- did I mention already I'm slightly unhappy about the Study Guide? -- this book conveniently includes a practice exam, which puts you entirely on the wrong foot. I failed it miserably, mainly on silly questions about APIs (which exceptions are thrown by the ejbLoad method? which of the following types is not an interface?). This is NOT the type of questions I got on the exam. The type of questions I got on the exam was (I'm making this particular question up): A company has an e-commerce website designed with technology X and Y which they want to redesign to JEE. They already have a black-box credit card authentication module and they are expecting significant traffic growth in the next five years, for which they do not want to switch technologies. Which technologies do you propose?
Also some interesting questions about security threats and how to deal with them that I hadn't seen anywhere else, such as denial of service attacks, execution of arbitrary code. It would have been good to have had more background on that as well.
Other books I read that I recommend for this exam are UML Distilled (Fowler) and Design Patterns (Head First series).