I have gone twice - End of August very hot, and Mid April - very chilly. Each experience was different but wonderful. My August treats did NOT melt nor were they less yummy because of the heat.
In August, I was very very warm. The cold fruit and chilled desserts tasted wonderful with the heat. I even had some coffee (also had iced cold tea)
In April, we were very cold. Jackets, etc. The desserts obviously were very very chilled. I almost would have preferrred something warm, like a warm filled cake. But it still was wonderful.
The price you pay is for the area, lack of crowds, and the wow factor of being right where Tink flies. Too many people are trying to justify eating enough desserts to cover the price and getting sick. I did NOT eat an over abundance of desserts either time. Did I feel I wasted my money - absolutely not. I was too excited to have a chair over the Main Street pavement, great conversations with other famililies and the ability to actually hear them, and the lack of tension that comes with smaller crowds.
My mother always taught me "to each their own". If this sounds like something that will make you happy (not necessarily in a sugar coma) by all means try it. Well worth the money in my opinion.