I've done the whole Insanity program. It appeals to people who like a lot of cardio and body weight exercises. It's basically a whole lot of calisthenics for about 30-45 min. Most workouts made of circuit intervals, except the cardio ones which have no breaks b/t the intervals. The program definitely builds endurance and you feel wasted afterward. I liked except it gets a bit repetitive towards the end. Shaun T is good at what he does though.
