While the study guide is minimal, it is intended to be. And the topic list is essentially your list of what to learn in order to pass. Don't worry about the big topics, but look at the small ones, rate yourself on a scale of 1-3.
- I know it
- I kind of know it/I need a little bit of review
- I have no clue/I want to build it to see if I understand it
Forget the 1's
Start learning the 2's
Work your way into the 3's
I would say that this advice could be followed for any of the certification exams.
As for the developer certification specifically, the Force.com Fundamentals is good. The Force.com workbook. And don't overlook the online help and training. When the exams are reviewed, the first point of reference for any question that needs to be modified/clarified is the help and training.
A few weeks before your exam, go through the current release training. Every question for every exam is reviewed every single release. If you began your prep in Winter 13, but your exam will be on Spring 13, you might be relying on old information.
Finally, I always caution people about practice exams. Because of the always changing nature of the platform (and by extension the certification exams), that person who wrote those practice questions a year ago, may have been spot-on correct then, but a year later they may be out of date. Unless the questions you are using list the release they were written for, don't rely on a successful practice exam to tell you you will pass our certification.
I teach our Developer curriculum (including DEV401). That's my job at SFDC right now. Those people who go on and get their Developer Certification after DEV401 invariably tell me that it was a huge benefit to take the course. Everyone who teaches it themselves has to be Developer certified, as well as go through our rigorous instructor certification process. So if that is an option for you. Yes. Take DEV401. You will not regret it.
Per http://certification.salesforce.com/schedules, Winter '16 Release Exams will be available on November 11th.
Based on communications to the Partner Community, though I have no one example I can cite on this, I would expect that until 401 is fully retired, you will still need to take your release exams as planned.
Best Answer
There are two clauses of the test-taker agreement that address this question. They are found in sections 3 and 6.
Section 3
Section 6
The first part (section 3) states clearly that the exam is confidential information that you are prohibited from disclosing.
When you tick that box, you are, in essence, agreeing to an NDA.
Section 6 states clearly that breaching the terms of the agreement is grounds for revocation of your certification.
In other words, violation of the NDA carries the potential consequence of losing your certification.
So what is acceptable?
I have seen examples of all of the following that have been accepted and tolerated by the certification team:
As long as these things do not rely directly on the content of the course, the confidential information you are asked to protect, you should be in good shape.
On the other hand, if in helping in the above ways, you do share confidential information, it is up to the discretion of the certification team and their legal counsel as to whether or not you get to keep your certification. I would like to think that each case would be evaluated on its own merits. A single mistake on a forum, for instance, is different from blatantly posting entire question sets to LinkedIn or Facebook. But in the end breaking the agreement makes a person vulnerable to the consequences outlined within. So share judiciously.
EDIT:
And if you are thinking of writing an article, or publishing your exam study guide, and you are concerned you may be crossing the line, you could always file a case on certification.salesforce.com and ask for the certification team to review your content.