A good point was made here.
Many CWI's simply took the test to make $ or more $$. Nothing wrong with that. The problem arises when they do not really care about integrity, honesty, or the safety of the public or property.
Then there are the people who really want quality in the part or structure when they are putting their stamp on the paperwork, usually with pride.
I used only my CWI for about 4 years before I had to start obtaining other licenses or certifications. This subject is discussed in another post as well. Your CWI can open lot's of doors These doors can lead to many different avenues besides just looking at welds. I am not waving the AWS flag here, just the facts. They have gotten ridiculuosly high with their fees for anything with thier logo or name attached.
Certification also provides validity when you make a call, legally. Just make sure your ducks are in a row - you've done your homework - or whatever when you make that call. Your reputation will follow your certification. Nobody cares when you do a great job, everyone know's when you do a bad job.
Additional:
People with an extensive welding background or are simply good at taking exams - do well on the exam and will say how easy it was. Then there are those who depended on good old fashioned hard earned studying to achieve certification. I went to the "18 year school of hard knocks" and studied for a year before taking and passing the exam. I knew the welding part, but did not know the NDT. Take the time and prepare, regardless of how you evaluate your own skill level, retesting sucks.