Just look at these stats, freakily close, almost identical career goals per game ratio!
Sergio Leonel Aguero del Castillo
Age: 23
Height: 172cm
(Independiente) 23 goals in 54 games [a goal every 2.35 games]
(Atletico) 82 goals in 195 games [a goal every 2.38 games]
(EuropaLg/ChampionsLg) 20 goals in 39 games [a goal every 1.92 games]
(Argentina) 11 goals in 27 games [a goal every 2.4 games]
(Career) 136 goals in 315 games [a goal every 2.32 games].
He's short-ish, fairly quick, works hard, not great in the air, fairly strong (but not particularly for someone who may play as a lone central striker), he's skillful, is a good passer, he plays well in big games against big teams often scoring goals in these kind of games.
Karim Benzema
Age: 23
Height: 184cm
(Lyon) 54 goals in 131 games [a goal every 2.43 games]
(Real) 28 goals in 68 games [a goal every 2.43 games]
(Europe - remember this is ALL in the CL!) 19 goals in 32 games [a goal every 1.68 games]
(France) 12 goals in 37 games [a goal every 3.08 games]
(Career) 113 goals in 268 games [a goal every 2.37 games].
He's taller, stronger, just as fast, holds the ball up better so will suit being a lone no.9 if he has to play like that, has much more CL experience, has scored goals against big teams from all over in the CL, i think his size and strength will suit the Prem better than Kun.