Depends what you want. In terms of pure goal scoring, well Erling is better. Aguero's best season still isn't as much as Haaland's worst. So there's really no debate to be had on that front.
I think most would agree that Sergio was better in his general play then Erling. But Erling is a bit underrated in this regard, he gets a decent amount of assists. Not sure how they compare statistically on that front, but maybe some statto on here can tell us
Anyway, we are lucky we have had both, so i'm just happy about that rather than think too much about who is better. I think it's splitting hairs really. Both excellent. Haaland being a freak goalscorer that breaks records and Aguero being just a great forward in general.
Haaland has that global superstar x factor though. He's really our first crossover global superstar. The others like KDB, Aguero etc were fucking great players and everyone knows it but Haaland is superstar level, regardless of if you think he's better or worse.