We have it. My uber-athletic 15 year old baseball stud stepson swears by it and has gotten significant results, even by not following the program the way it's laid out (cuz he's a teenager and doesn't think you have to follow directions.)
I, on the other hand, have simply read the manual and previewed a few of the workouts. I'm scared. My wife has tried the "less intense" yoga program. She's scared.
All I can tell you is that it will kick your ass
and deliver results. I promise.