For us, it was worth it...because we had 10 day non-expiry tickets and it allowed us to visit MK, while sleeping in one day and saving a day of park admission for a future trip.
Other than that, I personally wouldn't bother.
We didn't find it all that impressive.
We had a nice dinner at Liberty Tree, rode rides (Some with no lines, some with huge ones) and watched a few cute shows.
The fireworks were nice and so was the parade.
There
is free hot chocolate and cookies, which some folks really get excited about

. (They weren't like the treats the White Witch gave out in Narnia or anything out of the ordinary like that--just sugar cookies and hot chocolate.)
On a side note, we are considering the Pirate Princess party in March because we only have two days left on our passes. Passes are pricey for a family of 5 for a few days, and we aren't ready to splurge on 10 Day tickets again. We have a few other trips in mind now that the kids are getting older.
For this year, we plan on checking out Universal, but we can't see being near Disney without seeing MK, so like MVMCP, the P&P party will
hopefully allow us to maximise our stay.