I have the ACE Health Coach certification and it has been a wonderful addition to my personal training. I use it mainly in conjunction with my personal training services, and also offer health coaching separately. I am not familiar with the Dr. Sears Health Coach cert., so I am not able to compare the two–but I am very happy with the ACE cert. It was a well written program and has given me a firm foundation of how to help my clients create healthy habits and lifestyle changes. It has brought me to a new level of understanding my clients and their stages of change, and I see the whole picture of health and wellness much more clearly and defined.
I think the direction you go will depend ultimately on what you plan to do with your certification. Use it alone? In conjunction with personal training? As a supplement to your teaching for personal knowledge? Corporate venue? I would research them both and understand what each one is best suited for.
Hope this helps, and perhaps someone else will have more insight for you on the Dr. Sears program.
Best of luck to you!