Both deal with a similar premise where the main male lead is forced to live with a stranger while he is currently seeing someone. Orange Yane is much more light-hearted and takes a completely different path for the plot while Mama wa Doukyuusei is focused on drama and controversy.
Both Mangas have main characters who live with a young mother who has a much older husband. Conflict arises when the main characters sees potential interest in their mother. Me-Teru does the story different by the main character being a shut-in and trying to grow as a person. While Mama is a more traditional high-school flavor story with ecchi and drama filled scenes.