Attaining certification signals to the world that you are an expert at what you do. It validates your skills against current practices. This can be a real boost to your career as many companies value certified professionals.
This is the certification you want to attain if you are just entering the working world or within a few years after starting your first job.
With several years of work experience, you have developed an understanding of how IT fits within the bigger picture at your company. This deeper understanding of IT and business synergy means that you are ready for this level of certification.
If you are actively using RPG in your job, this is the certification for you. Finding people with current RPG skills can be difficult for employers. This technical certification shows that you are capable of doing the job.