I'm certified with AFAA
I'm certified with AFAA and wouldn't change anything about it. Yes, ACE seems to be more recognized, but clients can't tell the difference unless they are also certified. From my experience most of the job postings for entry level personal training positions require a "certification from a nationally credentialed organization/association." I chose AFAA because of the oral and written examination. ACE only has the written exam. The AFAA certification process was very tough as you REALLY had to know your stuff. That is, you are in a room with a pseudo-client and the instructor. That's it. The instructor gives you some different scenarios based on the client's background. Then, based on the types of exercises you're asked to instruct, you have to modify them to the client. That's just one example. It was really nerve wracking. Then you take the written test with everyone else.
I'm also certified with AFAA as a group instructor (kickboxing, step, etc.)and that was pretty much the same process except we were demonstrating our "moves" in a group and then had to instruct the class on our own for a couple of minutes. After that, you take the written exam.
Since I've been a trainer and instructor for almost four years, I've found the ability to articulate instructions and communicate with clients/students the biggest issue in training.