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person who wrote those practice questions a year ago, may have been spot-on correct then, but a year later they may be out of date.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.
I followed the transition track from advanced developer to the platform developer II exam. So I did not take the platform developer 1 exam, but got the certification all the same.
Take into consideration that these exams are reviewed and extended every release and it is thus likely that the questions on developing lightning will increase and so will their detail or complexity from what it may be now.
Having done nearly all other certifications I would interpret it like this:
- Know how to compare Lightning to Visualforce
- Know where you can use Lightning components and applications
- Read the high level help/documentation introduction to see what benefits are mentioned to both end users and developers.
- Understand how you develop (and deploy?) a lightning component
- Developer a hello-world component and try to get some data from a controller
- Do any trailhead modules on lightning components (may include the point above)
Best Answer
The best place to get more info on this is the study guide for each of these exams .
App Builder
The course recommended for App Builder is the same course that was needed for developer exam before .Remember that 401 is not the exam name and it was a course name .
Both the exams focus on the declarative features of the platform .The best place to get what topics to be covered is documented in the Study Guide
The difference I found between developer exam and App builder is App builder also focus on the latest features added to the platform like Lightning App Builder , Salesforce 1 Mobile Configurations ,Process Builder Automation,App Deployment and Application Lifecycle management.So Apart from reading previous content for Developer exam also focus on these Topics .
Platform Developer I
Platform 1 is very different than previous developer exam .This exam now focus on both declarative and the programmatic capabilities .It does not test your in depth knowledge of Apex and Visualforce but basics of apex and visualforce is tested .You should have clear knowledge of when to go for declarative features and when declarative features wont full fill your need .Again Study guide is your best friend here .You should have great command over building data models and logic using declarative and programmatic features .
Platform Developer 2
This is similar to the advanced developer exam we had previously .It includes multiple choice followed by assignment and essay exams .The candidate is also expected to know Integrations and best practices for app development and deployment .