My 2 cents (Cdn.) - Insanity lousy
I just joined this site, and am jumping in a bit late... I think P90X is a great general conditioning workout. Based upon your profile, if you are going RAAF then it will help with all the pushups you will be doing.
I like being able to pop in a disc and just follow along...the down side of P90X, hhmm... probably all the 'coaches' you will meet online trying to sell you stuff. Just ignore them. I bought Insanity, a mistake and a poor program. Basically it is the same program every day, lots and lots of knee jarring moves. Good way to get injured. P90X alternates weight training (low impact) with the more intense.
If you wanted to really be a beast, (and what I am hoping to do myself) is get Jillian Michaels Ripped in 30, 4 - 30 minute total body workouts that will humble you. Do 30 minutes in the a.m. and then a P90X in the p.m. That will give your metabolism a nit in the morning and evening.