I am wondering what some opinions are of using machines to boost past plateaus. I've been lifting for some time and have achieved considerable muscle mass, but lacked detail. I've been focusing my efforts during the last year or so on more concentration exercises. Mostly using machines, I've noticed that I've been able to lift more weight on my free weight compound movements as a result. I only ask this question because I know most hardcore bodybuilders tend to shun machines. Has anyone else found machines to benefit them with their bodybuilding goals?