I am by no means an expert, but here's my opinion.. I've been to the world 3 time (and I realized when I got back the last time that each visit was spaced out the exact same number of years!). I went when I was 2 (sister was 7.. More her trip then mine!), then again when it was 15 (13 years later).. As far as I remember we never used the dinning plan cause we drove, from toronto, canada to Florida, my parents and 10 year old sister so we packed a lot of food and also bough groceries and such. Then I went back when I was 28 (this past January), with my almost 8 year old son. It was his first time and he's an extremely picky eater.. He basically rotates with pizza, pasta (no sauce), fries and plain white rice as far as dinners are concerned and recently added Mac and cheese to his menu. Lunches he's huge into peanut butter sandwiches but our rule is if we eat out and I take a sandwhich it on,y has jam cause do other ppls peanut allergies incase he touches something before he washes his hands after he eats. Because I'd all this when we went in January 2014 I stayed away from the dinning plan cause I knew it wasn't gonna work out price wise, neither of us usually eats a lot, especially at lunch time. We did 3 character meals and even tho we stayed at disney property the entire time. We spent 2 full park days at universal, which would have wasted money if we were on the DDP. With that being said, I'm planning on taking him back novemeber or December 2015 and I'm budgeting for the DDP. His eating as increased (he'll be a few months away from 10 at that point) and so has the selection of what he eats. I also noticed that we ate a lot more counter service meals then I originally planned on us eating when we were there last and even tho we went with gift cards, we spent a lot on out of pocket expenses for snacks (and we went down with a suitcase full of food!).
What I did was basically pick at least one TS restaurant in each park and figured out with the menus if my son would eat anything from there and I'm pretty sure well come out on top money wise. 99% of the TS I want to try next time we go are character meals as well, and the refillable mugs are a huge advantage. We used those 4-5 times a day when we bought them last time so to have them included works really well for us as well.