We did the Illuminations Dessert Party in March and loved it. A few disclaimers: we love special events, Epcot and Illuminations. So going in, we assumed we'd like this better than the Wishes Dessert Party because we prefer Illuminations/Epcot over Wishes/MK generally. We don't love desserts, but thought this would be fun.
The day of the party, weather was poor. So they had to move dessert service part of the party inside to the Odyssey building. Shortly before Illuminations, we brought our desserts and drinks out to the viewing area. We don't mind standing one bit - that seems to be a big issue on these boards, but is not for us. We didn't hear anyone at the party complaining about the standing either. It was a happy, festive bunch on the night we attended!
The desserts included apple cobbler, some other fruit based dessert, blue velvet cupcakes with sparkly frosting (we loved those), tiramisu, ice cream (scooped with toppings, no mickey bars or popsicles) and several other items. I can't remember them all, but our impression was that Illuminations offered far less variety than Wishes but far better quality. At Illuminations, it was less crowded near the food tables and we saw less plate loading than at Wishes.
We loved the viewing location. And again, we had a festive bunch. While waiting for Illuminations to begin, kids (ours included) were dancing with the glow cubes from the tables in the Odyssey building and a CM near the FP location started a follow-the-leader dance thing with his glow wand. During the show, some of the dancing continued. Very fun.
In response to the question regarding the kids, our 8-year-old opted to sit (both inside the Odyssey building and outside) while eating his desserts and was perfectly content. Other kids did the same and he made a few friends (who became dancing companions!)
So we loved the Illuminations Dessert Party. We know there are many places to view Illuminations and we know the party isn't necessary for a good spot. It's just convenient and festive. We certainly didn't eat anywhere near $50pp in desserts or drink enough to make it worth it from a food consumption standpoint. But we were staying CL at WL at the time and the combination of appetizers in the club lounge and the desserts were so filling that we ended up not eating a traditional dinner. The price tag was easier to tolerate because we didn't spend $40pp on dinner that night. It was a fun experience and we'd definitely book the party again!