Another thing to consider is, are there specific places that you’d like to work? If so, what certifications do those potential employers value?
ACE is a great cert. I don’t have ISSA, but I’ve never had trouble getting a job with my ACE personal training cert.
The training model I find to be the most elegant of all is NASM. I’ve read their book cover to cover and appreciate their OPT model.
I want to make another pitch for NASM. One of the things I like about them is that they have several specialty certifications that all integrate into their OPT model and form one coherent entity.
Here is a review on the ACE cert if you decide to to with them.