You make it sound like you're comparing Ronaldo with Amauri.
Nani has been brilliant for Manchester and he's an amazing player. Not just that but he plays in a tough league, unlike Mickey Mouse league where Di Maria plays. He had 13 goals and 13 assist while season before that he had 13 goals and 17 assists.
Di Maria is a good player, don't get me wrong, but Nani is amazing. Would Di Maria do that in EPL? I fucking doubt it while I'm pretty sure Nani would eat those guys in Spain.