I've done both several times and they are both great workouts. The Cardio Power is Kickbox and then Boot Camp (or could be other way around, I don't remember) but I know by the end of the workout I am soaking wet with sweat and I am beat.
I like doing double cardio one day and the cario power the next day. I just like longer cardio sessions than the 30 minutes segments on the disc as is.