Actually, I believe, having dealt with a lot of different married women, that Middos is THE MOST IMPORTANT. It’s hard for someone single to imagine the concept that you will be LIVING with this person. Its NOT like your seminary roommate, for one yr. and then u go home for pesach and each person to his own home, and then at the end of the yr. u wave good bye. You are marrying someone that will have to love u and tolerate under all circumstances. Not just when u date hom and look beautiful. It is something that CANNOT be fathomed by someone single. Remember when u date, that looks, humor, …are a bonus…Fine Middos is priority. Dating is nice, but u must also find out information, How is he when he is angry, does he have refined speech (on the dates he will surely be on his best behavior), is he sensitive towards other boys….
BTW I do think it is important to marry someone in ur family background, not a priority but it makes life smoother especially when it comes to raising children.