We did this in March, and it was great! The ice cream was delicious - fresh tasting, with bits of vanilla bean all through it. The accoutrements were delicious as well, a huge cookie, and plenty of chocolate decorations! The kids loved theirs too - they had gummy worms as well. It was 7.95 per person, I think, or thereabouts.
When you consider they add an entertainment fee of $5 for people who attend a character meal without eating, you are really only paying $3.00 for this enormous sundae & cookie. That is truly a bargain for Disney! They gave us water at no charge, we only paid for lemonades for two of our daughters, and coffee for DH.
The character's attention was great. Chip and Dale spent at least 15 minutes at our table (It was a quiet afternoon!), and Mickey and Pluto came by several times as well.
We started our trip with this meal, and it may become a tradition! Test Track was only open this day during our trip, and my oldest really wanted to try it! I didn't think I would get DH to agree to go to Epcot immediately upon arriving, especially with Spectromagic only showing that evening. We really lucked out - we got Fast Passes to Test Track, rode Spaceship Earth, watched the Circle of Life, went to the Ice Cream Social, back to Test Track for our Fast Pass time, and still had time to hop over to MK for 7:00 Spectromagic, arriving about 6 - getting a great spot, and sending my oldest two over to Casey's to bring back a snack during the parade!