It dawned on me that I never posted a conclusion to my review in August of P90X Phase 1. I made it to Week 3 of Phase 3 when I hurt my neck badly doing one of the weight-training exercises. It took a couple weeks for me to really move it well again, and I didn't work out during that time. I got busy with the semester and decided I'd accomplished enough and needed to spend those hours with family and school instead.
I think making it completely through Phase 2 and over halfway through Phase 3 was a good accomplishment. During the late fall I would do an occasional Jillian's Shred but didn't work out much and got out of shape. I kept my weight in check, though (I lost some weight immediately following P90x due to loss of muscle mass).
Upon returning from the fattening holidays, I did a full week of Phase 1, which is the first time I'd done Phase 1 full-out without any modifications after having done nothing for a while. It was more brutal than ever, my numbers stunk, but it felt great.
I love P90X, it's been a great investment for me. But it's time-consuming. Every workout is at least 60 minutes plus you typically need time to shower and recover and that eats away at doing other things. My plan is to do it every other day so that I can get more things checked off my list in the off-days.
I also highly recommend the blogs and newsletters on their website. The P90X Newsletter has all kinds of eating tips and recipes.