Yup, I would say the Poly is the most kid-friendly and my kids (7,4 and 18 months) absolutely love it.
1) Big-screen TV,
2) kid-friendly snacks and meals (gummy worms, M&Ms, lots of fruit, brownies, PB&J, etc),
3) Great view of Cinderella's castle (mosquito-free fireworks and water pageant!)
4) Right next to volcano pool
5) Lounge never closes (great when little one will not sleep!)
6) Close to Magic Kingdom (my kids' favorite park)
If your kids really love a good pool, then you might consider the Yacht or Beach Club. Stormalong Bay is the best pool at any of the Disney hotels (IMHO).
Mike