The Dining plan can definately save you money. It's 37.99 per day for adults and 10.99 per day for kids. You have to figure how much you would spend for food normally, do you eat at table service restaurants a lot? Character meals? Those really add up if you do. If you eat at table service a few times it's generally worth your money to get the plan.
Plus, if you're on a budget like we usually are, it's nice to know that you can pick out whatever you want at the restaurants and counter services places and not worry about the prices, it's all already paid for. We used the
free dining last year and we said we would never go without it again. So we are paying for it this year in September. (We're renting DVC points, so no free dining for us

)
On the other hand, the only con I can think of is having to schedule your ADRs. We had always just winged it when we went and ate whenever and wherever we felt like. (Usually counter service) So it was a bit of an adjustment for us to be on such a schedule on vacation. July is a busy month, so you'll have to plan ahead.
Also, if your kids are right over the age limit (10 I think) and don't eat much, it may not be as cost effective for you to pay 37.99 per day for them to eat.
Good luck making your decision!
Jennifer