I did DAN exam chapter by chapter initially and whenever I put a wrong answer to some question, I went back to K&B, to get a clarification. Second time[after 1 week] I took all the chapters at a stretch with 15 mins break in between, 92% of the answers were correct.
So, I think K & B book is enough, if one can catch the point. Fortunately, some of the questions in the [my]final exam were from that book [I think 4 or 5]. If you can get good score in K & B book's each chapter questions, I think thats more than enough to get fairly good score in final exam.
Moreover, Kathy and Bert are the best, they motivate you through out the book to not to leave out anything in the book.
Side note :
I personally loved K&B book for SCJP and I bought their book Head First Servlets & JSP[for SCWCD] without second thought. Know what, I bought it for $52 in Seoul, though the book cost is $30+ in amazon. Ofcourse, worth the price I put, I passed out with 2 weeks preparation.[I already bought "Head First EJB", will take 2 weeks break before scheduling for SCBCD].