I've only stayed at POP and ASSP and while both were great I'd have to pick Sports - small resort, food court always had seats and wasn't crowded, bus service wasn't over crowded, short walk to the main building. I also loved the football field - with small children, it gives them a good place to run around and burn off energy!!
Pop was good too - great theming, good pools, good variety at food court, there was always huge lines inthe morning and never any seats for breakfast. Bus service was crowded and the resort was more crowded as well.