Hands down The Biomechanics is the way to go. I have been NASM since ’99 and it is great but I really believe in Justin Price. His methods are very simple and easy to understand. The difference in the two programs is that The Biomechanics is centered around clients in chronic pain and doesn’t outline a weight-loss or performance enhancement type programing the way that NASM does. So it probably really depends on who you service, but for ease of education, I pick The Biomechanics.