Steve:
Before they were killed during Loki's attack on New York, your parent's thought he was perfect for you. He was so polite to them and you. He always opens the door for you. Your little brother and sister weren't killed, so they get to see him all the time. They adore him. Your older brother thinks of him as his idol, wanting to grow up to be like him.
Thor:
They like him, but they think he's a little loud. But your dad can always find something interesting to talk about with him or teach him to do. Your mom likes how strong he is. Since you don't have any older or younger siblings, he doesn't have anybody to inspire but your dad. Which you made Thor promise not to influence him to do dangerous things.
Tony:
They think he's a little stuck up. But they trust your judgement and agree with what you choose. Your brother was glad you were dating a rich guy so you could buy things for him. He and Tony got along well.
Loki:
Your parents liked him. He respected them. Your little sisters like running around with him. Everyone knew of his power. Even though you didn't tell them that he destroyed New York because they never watched the news and they didn't live anywhere near there anyway.
Clint:
Your dad loved him because he really wanted to learn archery, and he could never find a good teacher. So when you introduced them to Clint, your dad instantly took a liking to him. Your mom doesn't mind him. She doesn't talk with him a whole lot, but when she does, they have some intelligent conversations.
Bruce:
They know what he's capable of, and at first they didn't think he was the right one for you. But you convinced them that he was the perfect one for you. Your brother adores him just because he can turn into the Hulk. Bruce is still trying to convince him that it's not good or fun.
Bucky:
They were a little nervous when you introduced them to Bucky, just because of his arm. Your little sister thinks it's awesome. She really likes shiny things, so she always wants to play with it, even though she can't. But after convincing your parents of what a useful thing that his arm could really be, they accepted him.