By the nature of your question, I would assume you are a quality professional of some type or form – especially now that you provide consulting services within this arena.  I find it most interesting that you have only three years experience as a quality practitioner, but now serve as a quality consultant.  Given such a limited exposure, I would assume that you are an employee of a corporation and that your consulting position is internally oriented.  If you are in a private consulting practice providing “for hire” services, I would be shocked by the nature of your question.  Therefore, I will frame your question from a positive perspective and assume you are an internal consultant.  Given this, you should begin your journey by designing a sound due-diligence plan – just like a consultant would design for a client at the onset of engagement. 
 
In this case, it would seem logical to initiate such a plan with a personal assessment – why do I want to become involved with Six Sigma?  Do I want to continue being a quality professional or do I want to align with the business side of things.  Do I want to align myself with Six Sigma or some other type of initiative?  Do I gravitate toward providing leadership to my peers or do I tend to offer technical support and let others lead?  What role would I be best suited for – Advocate, Champion, Black Belt, or Green Belt?  Do you first seek to advance yourself or your company?  How will a certification help your career?  How will a certification help your company prosper, especially from a business point-of-view?  How will a certification directly help your company’s customers – its shareholders?

These are just a few of the questions that should be asked (and fully answered) before committing to a given direction.  It must be remembered that a Six Sigma role is just that – it is a role, not a career.  It constitutes a temporary job assignment, not a formal position on the chart of organization.  Accepting a Black Belt position within a corporation is not a career change.  In my opinion, on-going professional career roles should be subject to various types and forms of certification; however, intermediate job assignments should not.  Therefore, it would be my advice that you seek a credential that recognizes your leadership and technical contributions.  Such documentation should not only exemplify how your contributions generated direct benefit to yourself, but to your company as well (not to mention the shareholders.)

Be recognized for what you accomplish, not for a “piece of paper” on the wall that says you passed some esoteric “certification” exam.  As we all know, it is one thing to certify “knowledge,” it is quite another to certify “results.”  Consequently, it is your results that should be documented, not what you know – your clients will be much more appreciative of the former.  There is an age old saying that circumscribes this issue:  Don’t ever attempt to create a talking pig, it will only lead to disappointment and merely irritate the pig.