FWIW, we went down this past spring break (March 21 - 28 - Easter week). Everyone kept telling us it would be the worst time in the world to go. Parks would be packed, resorts would be packed, dining waits a nightmare, etc.
I honestly have to admit that I didn't feel it was much different than our summer stays. Maybe it was because we were expecting the worse, it was surprisingly better! Our longest wait for a ride was 1 hour (Peter Pan) and though SSR was sold out, the only time we knew it was sold out was when we went to the main pool. Main pool was packed, but quiet pools were wonderful!
DTD was a little more crowded than normal, but with a little planning (make your dinner reservations so you don't have to fight the lines), it was a wonderful trip! I wouldn't hesitate to go down during a "peak" time again. Worst part...number of points I had to use for a 2-BR!!!