I have read both HFSJ and the Kit for my exam and passed with 86% today.
In the very beginning of my preparation when I was reviewing the material on servlets, and I've got some experience with them, it seemed to me that the Kit was better. But when I came to the topics which I knew much worse, HFSJ became very helpful. They contrast and compare things and they are trying hard to keep you awake, while the Kit just puts the stuff out as a brick. And when you are already tired by the end of your preparation, you'll enjoy the informal style of HF.
Also I must say that the quality of the book itself (HF) is much higher. In the Kit you get slips and omissions. And some things got me really mad, like for example, writing "Java technology programming language" instead of simply "Java" (to make the book thicker?
), or when as an example of a directive they use all the time <%a page language="java" %>, even after explaining that there are no other languages in JSP 2.0.
Some statements in the Kit are really doubtful, and they keep discussing details of buffering in JSP - and I didn't have even a single question about this stuff on my exam.
I have HF
EJB for my next exam, and I am not going to buy any other book.