I agree that everyone should go at least once. With that said, I have been to 4 MVMCPs since 2004. One was PACKED (early December) and miserably crowded. One had almost no crowds and the other two were so-so.
You CANNOT go there expecting low crowds and no lines. The time I went that was so horrible I waited 45 min in Tomorrowland just for a beverage. Main Street was all but impassable it was so crowded.
In 2010 Cosmic Rays was so crowded there was NO seating to be had. Main Street was again packed, but ride waits were 20-30 min.
I now aim for every 2-3 years. The hot cocoa is straight out of "just add hot water" mix and to me is NOTHING special at all and the cookies are pre-made, boxed variety. Not bad, but not "Boardwalk quality." For what Disney (now) charges for this event and for what perks they have taken away, I had hoped for better quality in what remained.....