WDW's QS restaurants get pretty old pretty quick. After 2 QS meals per day for a week, you'll wish you weren't on it.
Conversely, at $593 for 14 days and (I assume) 2 people, that works out to an extra $21/person/day to change 1 meal from a QS to a TS. Incrementally add that to the cost you already are paying for one of the QS meals and it easily works out to well over $30/meal without alcohol. That's a lot of freakin' money for a meal and pretty much the only TS restaurants that consistently cost more are Disney's grossly overpriced buffets.
Since being introduced in 2005, the Disney Dining Plan (DDP) has proven to be popular with many onsite guests. In 2005, DDP cost $35/night and included one Table Service (TS) meal consisting of appetizer, non-alcoholic beverage, main course, dessert, and 18% gratuity, one Quick Service (QS) meal consisting of non-alcoholic beverage, main course, and dessert, and one snack. Disney now offers several DDP options, with the Standard DDP being most similar to the original DDP. The 2012 price of this plan is $51.54/night. However, the TS appetizer and 18% gratuity are no longer included. When these are factored in, the equivalent price is around $60/night. An increase from $35/night in 2005 to $60/night in 2012 represents an annual increase of 8.0%.
In 2013, the DDP price increased another 12.5%.
When originally introduced, it was possible for the casual WDW vacationer to save money using DDP. However, with the changes and price increases since then, DDP becomes more difficult to financially justify every year. If you want to maximize savings using DDP, carefully map out your dining to eat the most expensive menu items at the most expensive restaurants. Also be sure to eat every morsel. Otherwise, there’s a good chance DDP will cost you money. For the hungry planner, DDP makes sense. Yet for many WDW guests, I suspect DDP offers considerably less financial benefit.
There are some who prefer DDP for nonfinancial reasons. Perhaps the most frequently mentioned is having the meals prepaid. If this is really important to you, consider using a prepaid debit card, which offers considerably more flexibility than DDP.
You're not going to like my recommendation but I'd dump the Dining Plan completely and pay a la carte. In the long run, you'll probably spend less.