Which exercise routine is better P90X or Insanity?

It really depends on what you're looking for. Insanity is pure cardio and plyometrics (Jump Training) and focuses on creating a leaner body. It is easier and I have found that it is known to produce faster but less drastic results. P90x WILL give you a ripped body if you eat less than your BMR (Calories burned by just resting) and really push yourself during the workouts. I myself do I hybrid of the two, replacing the Non-strength workouts of P90x, starting during the first recovery week. I received awesome results but the fact of the matter is, as long as you bring it, either workout will be effective.