How is a comparison mental? Both world class forwards. Sterling has acheived far more than Mbappe in the club game so far (Ligue 1 nowhere near Premier League).
Just because Mbappe is easier on the eye, doesn't make him incomparable. He's got a long way to go before he's at that level.
I’m always amazed at how poorly Sterling is viewed in this country, on the continent they see him as the most dangerous English player and hold him in high regard