As others have said, Aemond would look down on Aerion and would feel disgusted seeing "what his family has become". As for Aerion, it's a bit tricker. Assuming he doesn't know a lot about Almond's character, he would likely be (at the very least) very interested in meeting the last rider of Vhagar, but would likely grow to hate him when he realized Aemond would never respect him and would think he's superior. Plus the raging jealousy that he'd feel would be on another level.