I did P90x for a year because there is no gym in my neighborhood, and it was the only thing available at the time. It was a good program when I used it, but STS far outshines it. If anything, I found P90x to be repetitive. My first round of STS was the 3 month rotation. It went by so quickly for me. I could not believe it. Now, I've started over, and I'm doing the 6 month rotation. That's just how boring it was the first time.