It's an excellent rate and we enjoy staying at Swan/Dolphin. You said that you were on a tight budget, and that's the only reason I hesitate to strongly encourage you to take advantage of this opportunity.
Benefits: larger room, with queen beds at the Swan (heavenly beds, I'm told) and oversized doubles at the Dolphin; right in the heart of Epcot, where you can easily walk to a variety of other resorts to eat in a variety of restaurants; 10-15 minute walk to MGM or Epcot, if you choose; boats to both those parks; deluxe resort; choice of several pools, including a very nice grotto pool that is so relaxing.
Possible drawbacks: Restaurants and food in a deluxe resort are more pricey. No food court, so if you're planning to eat many meals there, that could be a problem for you. You can still bring breakfast stuff to eat in the room, and if you plan to eat primarily at the parks, I wouldn't worry about the absence of a food court.