When you think of tsunderes, the fun of it is the chase and eventually having your way with her as she turnes into ideal waifu material.
With yanderes, the chase isn't as important; it's what comes after the chase and keeping it there without the reality of your balls being chopped off. You know how some people are complete daredevils and are doing completely crazy shit? Having a yandere as a significant other and as a waifu is like that, but every day. At any time she could snap and drive that knife into your gut, but then turn regretful in the next second. Then comes the hot, but bloody sex...
and then the hospital being very suspicious when your wife drags you into the hospital bleeding severely yet AGAIN. To the point where they have nicknames for you.