I did it three times in a row, so 9 months of doing 1 hour exercises with no gains. Sure I was fit, but I did not make any muscle gains. I am now just as fit, but I am making muscle gains and maintaining my cardio without killing myself for an hour.
I realized that P90x is bullshit, Tony Horton did not get muscular doing those exercises. It all depends on your goals, if you want to be lean and fit, do P90X, if you want to be muscular and fit, do this program www.jasonferruggia.com