I'm glad you asked this question.
IMO, I found concierge w/ dining a waste. I would choose concierge over dining if making the choice again. Concierge is great for planning and what I like most about it, but the food offerings in the lounge looked great and we barely used them and felt disappointed. Not that we didn't get out money out of it, we just wanted to sample the food and it was too much food with the dining plan.
Breakfast was fine and we used it every day except for one character breakfast. We went to the lounge a couple of evenings during the light appetizers and it looked great, but we were so full. The idea of eating anything and then going to dinner on the dining plan made me sick. We did sample a couple of things in very small quantity. Desserts, wow, did they look fantastic. We could not eat any. We did have a few glasses of wine. The kids had some juice. They didn't even want cookies or any of the other snacks. We got glasses of the bottled water. (The whole bottled water thing annoyed me. I know people wasted in the past, but the tap water was horrid and we had to keep getting a couple of cups of water at a time, but I digress).
DS (10 years) even asked if we had to get the dining plan the next time we come! The CS meals were too much food. TS was too much food for us. We aren't light eaters, either. We had 8 CS credits left at the end of our trip. We used all of our Snack credits for water.
Obviously, my opinion is don't skip concierge, but do skip dining plan. (In fact, if you consider that you wouldn't order that much food, esp. if you may have an appetizer and/or dessert in the lounge, I don't think you save that much money. --
if you went when it was free you did 
-- I know people say they saved hundreds of dollars, sure, but would you have spent that much, if you didn't have the dining plan/ Maybe some would. We wouldn't have. Character meals may be the exception).
Honestly, by the end of the trip I didn't even enjoy food anymore.