NASM is top notch, as is ACSM. I’ve read the NASM book cover to cover and its OPT model of assessment and programming is a thing of beauty. I know ACSM is well respected but I haven’t read their book.
Another PT cert that I think is fantastic is PTA Global. I have attended workshops by several of the people who designed the PTA Global cert and they’re talented practitioners as well as presenters.
I have ACE and have had it since 2009. It’s been a good certification, and my job opportunities have been plentiful. If I had it to do over again, I’d do NASM or stick with ACE. I was 2 weeks from my NASM exam when I got a job that needed my attention. I’m glad I took the job but I regret not sitting for NASM after all the prep time I invested.