Okay, you asked for opinions, so I'll give you mine.
We went to
MVMCP last November. I coughed up the $$ for tickets, thinking it would be a magical experience for us; however, it wasn't.
My husband and I were at the park with his mother and our 3 children (ages 7, 4.5 and 4 months at the time). The baby was no problem - she slept in the sling and was very mellow. My older two; however, were tired at dinner and were lukewarm about going to the party, even after having gone back to our villa in the afternoon for quiet rest time.
I decided to press on because we wanted to meet the 7 dwarfs (the ONLY time you can do this!) and see Cindy's Castle lit up, parades, etc...and, well, I spent all that money! However, the crowd was HORRIBLE. They were trying to wrangle non-ticket holders out of the park and people with tickets were stampeding in. It was a mass of strollers and bodies everywhere. The shops were all mobbed and it was just chaotic and no fun.
To be fair, the night before saw VERY heavy rain and one CM told us that ticketholders from the previous night were allowed to come on this night to make up for the terrible weather. She said it's normally not that bad. I don't know for sure if this is correct information, just going on what one CM at the entrance/exit gates told me.
Tired kids + awful crowds = not at all a magical experience. We stayed for an hour, then left. Trying to keep the kids with us (not because they were disobedient; rather, because there were so many people we were clinging to each other at a few points), fight our way to the featured party attractions and deal with chaos in the dark was just no fun for us. I would not do it again - and I am a HUGE fan of all things Disney. This was the one disappointment we've had in our trips to Disney.
Now, I understand that we might have experienced a bad night - I've heard other people just rave about it (which is why I went!). Here are some questions to ask yourself:
1. Would you be upset if you spent that amount and it rained? Was too crowded? Didn't meet your expectations?
2. Is this money an amount you're taking away from doing something else? (Say, upgrading dining plan, taking a tour, buying souvenirs, etc.)
3. Would you have just as much fun going to the various resorts and seeing their decorations? We had a ball going to the GF, WL and CR and seeing all their decorations.
4. Would you do bodily harm to anyone in your party if they became ill and couldn't go, thus meaning you've spent money on their ticket and can't get a refund?

5. Are you a huge fan of Disney parades/fireworks? If so, this may be for you.
6. Always wanted to meet the Seven Dwarfs? If so, this may be for you.