After over 2 months of intense studying, finally I passed the SCWCD exam with quite a decent score. The exam in neither straightforward, nor difficult.
Here is how I studied:
1st round) read HFSJ thoroughly, paying much attention to every single thing except for the classic tags and wrappers. Additionally, I skimmed through the SCWCD book from Manning. Also, I did all the chapter mocks from the books. F.Esnault notes were very helpfull, too. And if you want to know even more than it's really needed for the exam I'd recommend M.Zaikin notes.
2nd round) skimmed through HFSJ (only stuff in bold and exam watches) and read exam quick prep from Manning's book. Then, I found M.Green page which is an excellent resource for revision (however it's not sufficient without an accompanying book)
Mock exams: HFSJ - 62% (after first round, w/o analyzing the correct answers) HFSJ - 72% (after second round, with the in depth analysis of the answers) HFSJ - 82% (one day before the exam) M.Green SCWCD final mock - 94% (please note how close it is to the real exam score) jdiscuss mocks - from 65% to 85%
Summary: without a shadow of doubt HFSJ is the compulsory material for the exam takers (I'd even say that the book alone is sufficient to pass). What's more, working on a non trivial project before/along with studying for the exam can help a little as you learn things subconsciously, not just memorize them.
Thanks to the books/exam notes authors and javaranchers