It's awesome.
The beginning might turn some people away because of some 11 year old's fanservice but don't let that turn you away.
It's actually really funny and badass, Sora is kind of like a Light, L or Lelouch, only difference is is that this guy is a weirdo shut-in that lives in a fantasia world.
Not to mention, unlike anyone from Death Note or Code Geass, Sora and Shiro never lose, no matter how grave the situation.
Just watch it, it's badass, and hilarious.