It is NOT a Code Geass rip off. The main character is nothing like Lelouch. Guilty crown's protagonist is a generic as you get (think weak, no self confidence, girl he admires from afar, absent parents etc.).
However, where this anime excels is the quality of the animation. There's beautifully detailed back grounds, characters and (when they get round to it) fights scenes.
So, if you don't mind a generic story, sit back and enjoy the animation