It is SO worth it, especially if you have a "princess loving" child! Cinderella has been there every time we have been the other princesses tend to change, but not Cinderella. We have had at one setting, Cinderella, Belle, Snow White, and Aurora. My husband calls at 7:00am exactly 90 days in advance and requests the earliest reservation. We try to get the earliest for several reasons...very good parking if you are driving to MK (we had spot #1 last Feb), the dining room is slow to fill up, so you may get more than one visit from a princess, your reservation also allows you entrance into the park before others, so Main Street is almost completely empty! A great castle picture time! My daughter, 3 wore her Cinderella dress and was dancing her way down Main Street with the Disney music in the backgroud on a beautiful sunny day for her "date" with the princesses! What a moment!
Regardless if you have a little one with you or not, the atmosphere is wonderful, the food is nice, with a very low princess to child ratio, and a chance to say that you were in the castle!
I would highly recommend trying it out! Enjoy!