Most people call it fan service, it slightly is but it's not.
The story is great!
Someone who hasn't read the manga may say it sucks but truly, the story is deep and interesting.
The Anime just hasn't gotten to that point yet.
The music is okay, it's anticipating and emotional.
Here are 2 examples.
Emotional: Sister Ost
Anticipating: Aria Ost
The art is good also, good enough to lable Satellizer as the cutest anime character by far.
The character personalities are well to, it's very unique.
Over all, one of my favorite anime's and I'm begging for a third season.