My sister has it, she said she threw up after the ab work out. My brother in law said that it's really geared towards highly athletic people, but that you can modify the exercises for your level.
Yea, P90x is a really tough workout. But its worth it if you can get through it. I lost over 35lbs in just the first 2 months. If you are looking into losing weight naturally, and can commit to it, you should check out the P90x Workout.