Extremely quotable, bad-ass, and fun, 300 is a movie to remember. Zack Snyder knocks this movie's special effects and action out of the park and does justice to the comic.
But lacks of coherence and it seems you are watching a fantasy movie instead of a historical movie (i can say the same for Miller's graphic novel)
Although is a great adaptation of the mentioned Miller's work, fails in telling the story to the people, watching the spartans fight for a weak purpose and the persians portrayed as the bad guys fighting the "heroes" whose purpose is even more weak.
A movie to entertain, nothing else.
Short on substance but grand in storytelling, 300 is atmospheric pleasure.