Most Shaco's I've seen aren't that great or I guess I just compare them to myself sometimes too much. I've played so many games with him, I know the mistakes and have seen them so many times by myself and others. You eventually get the jist of Shaco after like 100 games with him and by jist I mean you understand him. He's not an easy cake walk.
I find Teemo hard to pick up and play properly because he just doesn't feel natural to me but others claim he's easy.