We are going on our first WDW vacation Monday, we too wondered if MNSSHP was worth the extra funds. I did a great deal of reading and The whole family said YES! We love Halloween anyway!
From what I have learned, the candy, the characters in costumes, the parades, dance parties and rides easily accessed. It was well worth the money to go.
Not only are we going to WDW we are going to a special PARTY! Where better to trick or treat than at WDW/MK.
Of course like I said this is only what I have read... but I feel confident that I will not be disappointed. We return on 9/23 so I can post what I thought of it,,, special things I saw.
Mickey's Not So Scary Halloween Party is Definitely worth it!! This will be our 3rd party when we get there in October!! The tickets say you can enter at 7pm but they let you in at 4pm. You'll see characters you won't see anywhere else & they have a special parade and a special Hallowishes fireworks!!
There is a really long thread about it on the Theme Parks & Strategies boards (pretty sure that's where it is)
You WILL not regret going! We did the Christmas party last year & my kids wanted to go back to the Halloween party.
We were going to skip it however after doing some more research have changed our minds and decided to give it a try. I went to this page: http://www.wdwinfo.com/holidays/halloween.htm
Remember, if you pre-purchase your tickets you save a few $$ and you're guaranteed to get in. One worry I had is if we waited to make a spur of the moment decision, the party w/b sold out already.