Based on our two MVMCP experiences in 2003, I will give you the opinion that depending on when you are potentially able to go to MVMCP makes all the difference.
Our first night at WDW on 12/14/03 was a Sunday. We checked in as opening day guests at POP and then at 4pm went to MK with just our MVMCP tickets and started the fun. We rode everything that we wanted to ride and most rides were more or less walk ons or 5 minute waits. Being that we are both adults with no kids, it's easy for us to go until midnight and that is exactly what we did. We had a blast and a half. We got the photo, hot chocolate, and cookies. We skipped most of the shows, the parade, but we caught part of Wishes while we rode BTMRR and it was magical.
Our second night at MVMCP was 12/19/03 and it was the last night of MVMCP and just happened to be a Friday night. It also was a sold out event. NEVER AGAIN!!! The place was too packed for my comfort level. We love low crowd value season touring, so seeing Main Street packed from the train station to the castle all the way across the street and sidewalks was a little disheartening. I told Gabby that I was so glad that that night was not our first experience at MVMCP or else I would have been so disappointed. We had a good time, but it was not as special as that Sunday night was. We saw the parade, we watched Wishes, got the photo, hot chocolate and cookies. We had a good time with the characters in their holiday attire too. But, it was just too crowded.
IMO, MVMCP is a great way to maximize your pixie dust on check in day. If you arrive on property early and have the evening to kill, it's a great jump start with some quality entertainment opportunities. I think that as long as you are able to do this on a Sunday, Tuesday, or Thursday night, you will be fine. The 12/16 MVMCP and the few that follow will be more crowded because it's the normal time that the crowds are building towards Holiday levels. So, like I said, it all depends on when you are going and what you want out of it to say if it's going to be worth it to you.
FYI, we are going to MVMCP again this year. We will be going on our first day there which is Sunday 12/11/05. Good luck making the decision. Maggie