The following is my response to a question on the now-defunct testing.stackexchange.com. The question was "Is there a good tester certification?" and my answer:
Good for whom?
This tends to be a loaded question with almost religious fervor. Several industry notables have come out strongly against certifications. James Bach posted his objections in a compelling argument. It is a good place to start for the anti-certification argument.
Good for Employers?
As a hiring manager, I have only seen people with certifications listed on their resumes a couple of times. It was an indication that perhaps these individuals are taking an interest in their careers more than just a job. Did the certification sway my opinion of the applicants? No. Just a minor data point.
Good for the Tester?
I do think there can be good from getting a certification for the tester. However, that good does not come from getting the paper that says they are certified. The good comes from reviewing the requirements for the certification, identifying gaps in one’s knowledge, deciding whether it would be good to fill in that gap – it might not, and learning something new so it can be applied to the day to day job.
Good for the Certification Body?
Almost definitely. The certification body gains strength with the number of people who get certified. There have been examples of certifications which are really a mechanism to sell training. It is important to look at the certification body and what their motives are. What is good for the certification body is not necessarily good for the tester nor for an employer.
What is one to do?
First – look at what the certification covers:
Second – Where are you strong? Where are you weak? Are the weaknesses areas where improvement will help you personally and professionally?
Third – Identify for learning and how to fill in the gaps you care about.
Fourth – Decide whether the certification has meaning to you. For some people, working towards the certification is the motivation they need to fill in the gaps.
In any case, if you can speak to the various points covered in a certification and can provide real world example where you have applied the areas of knowledge, you will be able to convince an employer you know your stuff.