I personally like Beru better than Fuyumi. Fuyume is just your typical damsel in distress, and she as a character doesn't progress the story at all, only her circumstances propel the story. While Beru is a unique character with interesting personality and her battle with Staz kinda arousing
I'm just going to say one of the simple yet main reasons why I prefer Fuyumi. Beru's attitude towards Staz, that whole bitchy attitude. She doesn't have an annoying amount like punching him hard for any little embarrassing reason but she does have attitude which makes a character. But once it gets too actual intimacy she becomes Fuyumi-level. I would like her more if she still acted cool.
Fuyumi is that damsel in distress thing which I don't like but I have two bad choices so I'm going with the one who isn't a emotional mess.
Hopefully someone calls me on my bullshit with a accurate rebuttal on my inaccurate description of both because I have only read Blood Lad once a while ago and now I only read the new chapters that come out (also once).
Also, my reasoning is based on real life. Don't act aggressive towards me in an annoying way. I'd rather you be timid than annoying.