I'm in my 9th week of the Classic rotation (followiing it pretty much to the letter except for an occasional extra day off in the beginning, substiting other yoga for Yoga X about 1/2 the time, substituting a different kickboxing workout for Kenpo 1/4 of the time, and adding a bit of extra cardio about every 3 weeks). I'm also beginning to add some supplemental heavy leg presses on my Soloflex Rockit once a week because my butt is smaller, but not in a good way. I want to get it rounder and higher.
The results I've seen so far are a much buffer (more defined) upper body, a midsection that's on the verge of a 4-pack (rather than on the verge of a 2-pack like before), leaner legs. Everything's a bit tighter.
Other performance-related results are a strength increase (every time I do a P90X strength workout, I can lift heavier or more reps); greater flexibility, greater ROM in my joints. I'm also able to do quite a few push-ups on my toes (whereas before, I avoided these like the plague). A tight spot in my upper hamstring/glute area that I've had since 1999 (I recently came across an old workout log that said when it started) has loosened up and no longer bothers me. My geetchy shoulder (troublesome since a bout of tendinitis and impingement problems several years ago) feels much better, has better ROM and is stronger.
I'm not following their nutrition plan at all, but I have cleaned up my eating a bit by avoiding tempting junk and processed foods and increasing veggies. I didn't buy any of their supplements or recovery drinks or bars, but I do have a Power Dream chocolate soy beverage after I work out. It has a similar macro-nutrient (protein, carbs, fat) breakdown to their recovery drink.