I have an AFAA group ex certification, and will likely keep it for now (I’ve been teaching classes for over 20 years). However, I do agree (and if I had to choose all over again), that ACE has a quality certification. I have ACE for personal trainer and health coach certs. In addition to the quality of their programs, the ease of renewing my certs together is a plus.
ACE is highly regarded, and their workshops and continuing education are superior. That’s just my plug for ACE, but good luck whatever route you take!