If I were you I would opt out of MVMCP. The hot chocolate
is watery but the cookies are actually good (Snickerdoodles I think?). I'm SO not a parade/show person either so we usually just ride rides during MVMCP (which, with the increasing popularity of MVMCP, most of the rides are not walk on but the waits usually aren't that bad, maybe 10-15 minutes; but we went on a Tuesday so weekends would probably be worse). I saw one Christmas show back in the day at the old stage show area in Tomorrowland and all I can think about when I watch shows with characters is what the person inside the costume is thinking or why grown people are waving to someone inside of a costume

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Also, another thing to throw on the 'ol Cons list is weather. The weather is very unpredictable in December and if it's in the 40's and raining (like it was during our MVMCP night our last December trip) it makes for a) a crappy night or b) a waste of $100 if you don't go. Of course that's assuming that you're buying the tickets before the night of the MVMCP you're going to.
One of the only reason we've done MVMCP three times is because MK doesn't stay open terribly late during the beginning of December (and night EMH are far and few between during MVMCP times) and we loved being at MK at night. But after our last time we both agreed that it was such a waste of money when we could be at other parks that are less crowded because of MVMCP.
All of the exact same decorations are up at MK on the other nights (except for the one little place on Main Street that shoots bubbles, er, snow). I say save your $100, go on another night, and buy all of the cookies and cake your heart (and belly!) desires

, but of course that's JMO. Honestly, I would say give it a try at least once if you had kids or liked parades and shows.