Hi Linda. There are several certifications out there that many consider the “gold standard.” However, I’ve found that few trainers will agree on what is “the most preferred” or “best.” I truly think that the best of anything is what we as the practitioner make of the education and skills that we acquire through the certification process, as well as what we do AFTER receiving the certification (e.g. continuing education, research, constantly challenging ourselves and our knowledge base).
Like anything else, the education (or in your question, the certification) that any of us receives is only as good as the person receiving it. There are many wonderful trainers in our industry, and they all come from a variety of backgrounds as well as certifications. My advice to anyone in our industry, keep learning, keep challenging yourself and your knowledge, and make the most of what you’ve learned, no matter which agency issued your certification.
I hope that this helps.