I self studied and passed ACE on the first try. Most of the questions were just common sense questions.

What should you do if someone who has an injury wants to start a workout program?
A. Nonsense answer 1
B. Nonsense answer 2
C. Nonsense answer 3
D. Get medical clearance from a physician

NASM is similar to ACE. I had a.... 'non original' copy of the text book

most certifications are just a tool to make money. The only respectable organisation is NSCA. They also hold the CSCS certifications, the gold standard for trainers