I am a variety nut and have a very hard time sticking with rotations. I did P90X2 up until the end of phase 2 and then got sidetracked with my other lonely workouts that were calling my name
I never did get to phase 3 but am interested in trying those workouts. I found phase 1 and 2 extremely challenging from a balance and doing balance work with the stability ball and med ball, some of the moves required a great deal of upper body strength (that I don't have). A couple of the workouts in phase 2 had a ton of pullups in them, some of the variations I simply could not follow safely. I did feel that I had to modify A LOT and was a bit frustrated that the only modifications shown were that of the travel version which was completely different than the regular version. So yes, I will admit that I was frustrated by my lack of balance and upper body strength to do a lot of the moves and at times they literally felt impossible. I did see some improvement and will have to get back to it soon. My favorites were the core workout in phase 1, the ab ripper workout and the arm workout in phase 2 (probably because it felt more traditional and had no pullups).
Just my 2 cents.