I agree with others who have posted before me, but I can tell you about my experience...
We go in winter, when crowds are low and weather is iffy. We're willing to take that trade-off for low crowds (and I mean, walk right onto every ride... our first trip there were NO lines whatsoever!!!)
Anyhoo.... if you get a good CS rep when you call, they will take the time to go through the numbers with you. For our first trip, there was 40% off the room, or
free dining. We ended up taking the 40% off and paying for the same dining plan that was offered for free. It ended up being cheaper by about $200 over the 1 week vacation.
For our 2nd trip, there was 30% off or free dining, but FD was only applicable if we arrived on certain days. So we had to arrive on a Thurs to take advantage of it, rather than our normal arrival day of Fri. In the end, with flights and whatnot (we were fighting Superbowl crowds in our hometown), the discounts and such made it worth it to arrive at WDW on Thurs, and take advantage of the FD. 30% off would have worked better if we were doing Fri to Fri, but we ended up doing Thurs to Sat (with a week in between).
If you don't get FD, will you still purchase the dining plan? We did because we liked the mindlessness of it when we were on vacation. We were also ok with being leisurely tourers, especially after we got there and saw the lack of crowds. For us, getting the DP was a no brainer, and that made it easier for us to account for the cost, since it was a set price.
If you book now under one discount, and a different discount comes out later, you can always call and have them run the numbers (I did this many times!). If the discount comes out better with the new one, they can modify or re-book your reservation to accomodate the better discount for you. If you do it this way, at least you know that your vacation is already booked, and you have a room "reserved" for you already, kwim? At least you'll already have something booked, and if something better comes along, you can make alterations to your existing reservation.
I hope that helped.
