I vote for VWL. We love going to F&W and try to go every year, but it is our trip "without kids".
Both resorts are nice but our kids favoured VWL. The set-up with the quiet pool just around the corner from the feature pool (and the pool bar in-between) has worked well for our family. The nearness of Fort Wilderness and the ability to rent bikes and go touring for an afternoon is also fun. Both have a beach and movies at night outside. Depending on the age of the kids, they can be hard to keep track of at Stormalong Bay. We always favoured resorts where pool time isn't stressful on the parents and everyone can have a relaxed afternoon (between morning and evening trips to the Parks).
Either way both resorts are awesome, our family just prefers VWL!