I just got back Sunday, and we went to MVMCP on 12/14. It was way more crowded than I expected. My mother wasn't feeling well, so we had to aim for the 9:00 parade, which meant nabbing a spot as soon as we got through the gates. By the time the parade and fireworks were over, the place was packed with people. I only rode one ride, and didn't see any shows. This was my fifth trip to the world, and I have never seen MK as crowded as it was that night (until the following Saturday, of course!) I remember thinking at the time that there were way more than 20,000 people there, and now I understand that Disney may have sold as many as 40,000 tickets for each party. I don't think I would spend the money for the party again, if I was going to be at the parks the same time that the Christmas parade was running during the day, which did happen Saturday.
On an upbeat note, the Candlelight Processional was worth every bit of money for the dinner package. It was simply extraordinary, and is definitely something I would return to see.