I can't speak to the late dinner and catching fireworks, but I do think it's worth it at least once. I must admit we are usually on the dining plan, so there's not as much sticker shock over the bill.
You first check in at the podium downstairs and wait to have your picture taken with Cinderella. You'll either head straight upstairs to your table or wait briefly to be called if it's not ready yet. Up the curved staircase into the lovely dining room. Unlike many character meals, it's a regular sit-down where you order from a menu instead of a buffet. During the course of your meal, there will be a little "wishing star" ceremony and each child gets a plastic star. Each child is given either a sword or magic wand keepsake by their server. The princesses will each come by your table one at a time, visit with you a bit and pose for pictutres and/or sign autograph books. I last traveled with a pretty big group and between us we tried just about everything on the menu - we all enjoyed the meal and found it very tasty.
I really enjoy CRT and meeting princesses in the beautiful castle while sitting and eating vs standing in a line!