As a neutral I think Rashford is better but I've always felt Sterling was a bit overrated anyway. His touch is erratic, his finishing can be extremely bad and his all round game IQ is lacking in comparison to his teammates. The other night was the perfect example, he could've rolled Jesus in for a tap in but not once did he get his head up and look instead opting for a powderpuff shot off the post.
Rashford has more goals, more assists, a higher conversion rate, a higher shots on target rate, more dribbles completed all while playing less games and for a vastly inferior team (no offence United fans).
Neither are the best English player atm though. Alexander-Arnold is better than both.