I too prefer the Boardwalk. I like all the dining choices (bakery, sweet shop, carry-out pizza, ESPN club, etc) and the atmosphere of the Boardwalk. I think the 11 yo would prefer SAB at the BC/YC, but the 5 yo may like the BW pool better. When we were at BCV last year our kids were 6, 4 and 3. They love water slides but because they couldn't swim weren't allowed to use it at SAB. But they could use water wings and go down the slide at Boardwalk. Also, SAB is *so* large it can be hard to keep track of the kids. But with the convenience of both resorts to MGM and Epcot, I think you'd be happy at either! Have a great trip!
jeff