We really like two of the dessert parties. The reserved area for the fireworks for my DH is priceless. He does not handle heavy crowds at MK well, we seem to have bad experiences while getting a spot and waiting (people showing up last minute right in front of you, being pushed, I got ran into by a stroller and took out a chunk of my skin around my ankle). We try to avoid MK fireworks unless we are watching from a party viewing space or from the Poly. The food and desserts are wonderful, but if you think of the cost of the deserts by it's self than it's not a good value. For us it's all about the reserved space and enjoying ourselves.
Starwars party is the same as above, you get a great place to watch the show and good food, deserts and alcoholic drinks!
Illuminations Desert party for us is something we need to do, there are so many places to watch Illuminations that are not crowded. We just grab a drink and watch from an uncrowded spot.