Well, I think most Ryukishi's VNs need to be read at least twice if you want to properly understand them. I personally read Higurashi after I already watched the anime adaptations, and I was really impressed with how well-written and filled with small unnoticeable details it was. To be honest, I think that it probably made me enjoy it even more than if I read it blind. The problem with Umineko is that it's just way too long. I've been wanting to reread it for years, but, honestly, I just don't want to spend 100 more hours on a story that I already know, no matter how much I love that story. Even if it probably deserves it, but, well...