Re: Sergio Aguero
I was fortunate to see him played @ the U20 WC where he was the MAN among the boys (that included Suarez, di Maria, Cavani, Pique, Mata, Sanchez, Vidal et al).
Aguero not only scored the goals (to win the Golden Boot) he made ASSISTS (to win the Golden Ball) to help Argentina win the Cup.
He is the MAN as evident with his 2 assists today. Ask him to show his left foot and he will score too ;)
So when you need to compare him with the others the U20 WC ( a good indicator of the potential of future senior players at the World Class level) is a yardstick I recommend.