we went this past weekend. To be honest, that part was a real disappointment. They had a section marked off (of course on the complete opposite side from our seats) for the Princess event, and all that was there was a small section for the dress, a picture of the princess, a few nicknacks, some figures of other characters (like the mice in Cinderella). You could go and take your picture with that stuff, there were not any actual princesses there. I was upset that we were running late, we arrive and really there wasn't anything to be early for! But the show was FANTASTIC! We had terrific seats and really enjoyed ourselves. The only time my children spoke, once the show started, was to say they wanted food! I have 4 year old twins, and they loved it.
My daughter wore a dress, it wasn't the dress up kind. It was one I bought at the
Disney store in the summer (white with pink sleeping beauty scene). There were quite a few dressed up.
The one tip I would give, they have sections set up for pictures with props. The one when we walked in the door was Tinkerbell, well we bought this for $20, and then as we walked around to the princess dresses we noticed there were two others, one for cars, and one with Mickey and Minnie. I was really disappointed that we bought early. When we asked the girl at Mickey Minnie if we could give her the tinkerbell and get one with them, she said they were not together so we would have to buy a new set. We actually did buy a second picture ($12-without magnet frame) and she gave us two copies since she felt bad. So I was pretty happy with that.
If you have the light up things (like used at Disney Fantasmic) take them with you. The ones at the show aren't the greatest (my daughter got one and we had to trade it in by the end of the show, she didn't wear it out as it was only in her hand for about 20 minutes) and then the new one they switched for is already acting like it is out too. The lights won't stay on for long. So I guess I will have to get her another one later.
All in all, we had a great time.