Yes. I also discovered PB through Mark's link in the P90x program, and since getting more entrenched in primal nutrition and the lifestyle Mark encourages I have found myself skipping P90x days more frequently, and not due to a lack of motivation or energy. Regardless, I'm still seeing incredible gains in body composition despite the fact the needle on the scale hasn't budged in two months. All the fat around my belly is becoming muscle in my chest, back, shoulders and arms, and I couldn't be happier about that.
I think one element to consider with P90x though is that 15 minutes of the workout is normally warmup and cooldown, plus there is a lot of lost time throughout each workout where Tony explains each exercise. We need to learn to better motivate ourselves and stop relying on Tony Horton and our DVD players to do that for us. I mean, eventually you shouldn't need a video to step you through eight variations of pull ups and eight variations of push ups. After two months of watching all 12 P90x DVDs six or seven times each you can pretty much roll out of bed and hammer out 16 bodyweight exercises to failure in 20 minutes bookended by 5 minutes of warmup and cooldown.
This is my undoing anyway. I waste too much time deliberating between doing the P90x DVD workout and watching that nights baseball or basketball playoff game, when I should be watching the sporting event I want to watch and enjoying the leisure time, while intuitively doing the curls and squats and bodyweight exercises Tony has taught me off the top of my head.