I think most part has already been said in this thread.
I'm Brazilian and I see him play every week. This kid is a MONSTER.
U know, South American football is waaaaaaaaaaaaay dirtier than European leagues. Italian football is tough but loyal, most of times. In Copa Libertadores, the players go to Neymar to literally break his legs. if you watch a game played in Argentina, Uruguay, Chile, you will know what I'm talking about.
And the kid NEVER gets hurt, he plays like 60/65 games a season and is never tired or injured.
He had a diving and showboating problem 2 years ago, when he was 17. But he's changed, he's waaaaaaaaaaaay more mature. His hair may lead people to hate him, but he also is a very hardworking fellow. He never missed a training session.
Unfortunately, he won't leave Santos before the WC/2014. And when he leaves, it's going to cost nothing less than 50M or some like that. But IMO it's worthy. U will guarantee 10 yrs of WC football, he's a guy you can build a team around.
Regarding other young Brazilian players, to me most of them are overrated. Lucas is skilful, quick, hardworking, good mindset. But he isn't intelligent on the pitch, it counts a lot. He looks down and runs/driblle like hell. But not a smart player.
Ganso is classic, 50 yrs ago he would be a genious. But he's just not dynamic/hardworking enough nowadays. I would not invest on him.
Damiao would be a good purchase for 20M. He's pretty young, great mindset, good skills and physical characteristics. I'd bet on him.