My personal favorite anime.
I'll try to explain it without spoilers.
It's about imperialism, terrorism, war, normal school life, racism, and politics, all at once. It blends awesome combat scenes with politics so well you don't get bored.
It's different. It makes you hate the main character. He lies, deceives, and uses those closest to him as pawns. He kills innocents, accidentally or otherwise. He bends people to his will. He breaks hearts. He does all of this: For the greater good.
He is working to create a world where innocents can live without fear of being persecuted. He does it so his crippled sister can live a normal life. He does it to unite the world.
Anyways, it may look like a gundam rip-off, but I'd say its way better than gundam.