This may be depend on attitude of a person.....I have cleared both exams,i can say both exams questions are of same difficulty level but yes,some questions in scwcd are straight forward...you may know the answer or not...it was just a matter of remembrance.
As far the book is concerned, I recommend HFSJ 2nd edition for SCWCD 5.This is a nice book from oReilly...
We can not compare two certifications.
i would say SCWCD and SCJP has altogether a different objective.
Where SCJP is more toward gaining/learning Core Java concepts , SCWCD has more inclination towards Web Development topics (like Servlet and JSP)
SCJP has more Core Java concepts (Core Java like Serialization,Generics , Fundamentals,Threading) where as SCWCD has more functional aspects of Web development like Session Management, Cookie management,HTTP protocol, JSP custom tags etc.
Also for example if someone is working on Web Development work (including Servlets,JSP, EJB etc) and he starts preparing for SCWCD exam then he may find SCWCD easy.
Oracle Java Web Service Developer (1z0-897), Oracle certified Java 7 Programmer, SCJA 1.0, SCJP 5.0, SCWCD 5.0, Oracle SQL Fundamentals I
I passed it yesterday. I say SCWCD is easier than SCJP. It took me 2 hours and 45 minutes to finish SCJP while it only took me 1 hour to finish SCWCD. I consider myself equally well prepared for both exams.
However, it doesn't mean preparing for SCWCD takes less time.
There were no tricky questions in SCWCD. That means once you've read through the question, you should be able to answer it without performing complex logic calculation. Or you simply cannot answer the question because you didn't cover this point while you were preparing. Memorizing tag syntax and API plays a far more important role than in SCJP.
In SCJP, you always need to worry about whether the code compiles or not, while in SCWCD, you don't have that concern. That also makes it a bit easier.
I only got 1 drag and drop question in SCWCD and I got around 10 in SCJP. I hated drag and drop questions because they didn't allow me to reivew my answer.
J2EE design pattern questions are as easy as like giving mark away to you.
In conclusion, SCWCD is easier than SCJP. But you still need to spend quite a lot of time preparing for it, especially trying to memorize API...