His hard repetitions, super-fast "easy" run paces and brutal VO2 max workouts have caused thousands upon thousands of wannabe elite hobbyjoggers to go home devastated with injury and burnout.
The man is more dangerous than the bottle of whisky that shares his name.
Not saying he's a fraud, his books have great knowledge but I facepalm when I see a middle aged bloke trying to break sub-20 in the 5K following his plans. His training method was designed with elite athletes in mind, not Dave with the sore hip and two knee replacements.