So you decided to get yourself into prime shape. Good job, now must decide what kind of shape you desire. You must first ask yourself whether you want the body of a dedicated runner or a muscle maniac.
Initially, both programs cost the same ($ 119.85). However, if you decide to go with the P90X, you should be aware that you will also need to purchase some dumbbells and a pull up bar. Both of these are relatively cheap and necessary if you wish to focus on certain areas of you your body.
This is where the differences become most obvious. The P90X is designed to build muscle fast while improving cardiovascular health. Insanity will get you into top notch condition, but you will not be likely to acquire a six-pack. That does not mean that it is not just as effective as the P90X. It just means that it's focus is not muscle building. If your primary focus is weight loss than Insanity should be your choice because it burns the most calories.
The P90X workouts will require anywhere from 45 to 75 minutes per day for 90 days. You will see dramatic results if you stick to the workouts and follow the Nutritional Plan.
Insanity requires less time, but that does not mean that it is less effective. If you follow the plan, you will be committed to 40 minutes workouts for 60 days.
I hope this gives you a simple yet knowledgeable understanding of the two programs. Whichever one you decide on, I am sure that it will bring the results that you desire. Good Luck!