Hi Janice. As you’ve correctly identified already, there are many, many certification bodies out there. There are several factors in determining ‘the best’ certification, and many trainers and group exercise instructors will not agree on the BEST. So, with that being said, one way to determine the best is to look at your own specific needs and limitations. There are several factors to consider in obtaining your first certification. For example, COST, as you’ve already identified can be a major consideration. Also, ease of entry (by this I don’t mean take the EASIEST certification, but what I do mean is that several agencies require a 4-year degree in an Exercise Science – that could be a major detriment, and very costly, to someone who does not already have one). If your goal is to obtain a position in a local club or organization, then finding out which certifications that organization holds dear to themselves is vitally important in obtaining that first job (so try checking around to some local group exercise instructors to see which organizations they are certified through).
These are just a few of the things you should consider. I hope that this was helpful. Good luck!