3. Character Based Humour
4. The protagonist is an intellectual, pretty rare for a kids' show.
5. I haven't seen any other shows for girls, but it's nice to see the way that many of the characters aren't crammed into "girly" roles.
NOTE: MLP is a good show, but it's not a great show. Watch The Wire, Community, Venture Bros, Archer, etc. before watching it. Someone compared it to junk food, and that's a pretty good analogy. It's just fun.