I really try not to compare the two... But it is hard when you have no point of reference for average development. Their personalities are polar opposite, which muddies the water even more. Dd5 is so easy going, when compared to her extremely intense sister. We did a kid personality survey once though, and they both scored in the "spirited" range, even though we see dd5 as being a lot easier to parent. Maybe she just hasn't had as much time to show us all of her spunk!