There are 4 experiences. I have been on 3 of them. The only one I have yet to attend is the Magical Fireworks Voyage. This is out of the Contemporary Marina. It holds the least amount of people (kinda obvious, as it is on a boat), and is the most popular. I have only heard great things about it from my guests.
The Good Morning Gathering is at Tony's Town Square at MK. It is fun, and is better then a regular character breakfast in my opinion. Not only do the characters visit your table, but the invite you to come up and sing and dance with them. After everything is done, they take you for a private meet and greet with Mickey, and you can take as many pics as you want. When I went they had a park photographer there, and you could have the pics put on your photopass. Of course, they let you use your own camera as well. And Ursula is right about the eggs!!
The Safari Celebration Dinner was also excellent in my opinion. I love Kilimanjaro Safari anyway, but this was better then the day time one. Not only did they stop for you to look at the animals, but the normal storyline with the Warden that runs during the day isn't run. You also have not just a driver as you do during the day, but a safari guide as well, who will tell you about the different animals and things that you encounter along the way. Dinner was very good. It is cooked with african spices which anyone who has ever eaten at Boma or Jiko can tell you makes the food flavorful, not hot in a spicy way. I tried the lamb stew upon recomandation of a friend, and it was very good. This coming from a girl who **HATES** lamb!
The International Dinner and IllumiNations Dessert Reception is great! Dinner is served buffet style, and features items from Italy, Moracco, China, Germany, and has a kids area as well. There is music and storytelling during dinner to help keep the kids busy, and as you are finishing up dining, you are joined by some of the characters, (Minnie and Goofy the time I went) who dance with the kids. After dinner you are directed outside to the VIP viewing are for IllumiNations, where desserts and beverages are served, while you watch.
In all the guests that I have either booked on these experiences, or assisted that went on these experiences, I have only ever heard rave reviews about all of them.