My results:
It helped me get cut in the last month of my cutting process. Prior to insanity I was doing weight training and boxing to get my cardio in. Insanity is great for conditioning and fat loss. It will help you gain muscle if you have very little muscle but I HIGHLY recommend incorporating weight training into your routine.
All you really need is some good dumb bell routines, bench press, military press, and some sort of leg workout.