I think it depends entirely on the individual horse. I have seen some that are absolutely gorgeous and others with nearly identical markings that just looked funky. I think a lot of it has to do with the horse's head conformation as well. I really don't care either way about blue eyes but I will say that blue eyes on a solid colored head is really striking.
I thought Prissy had a very unique bald face. One of her eyes was half blue and half brown. I can't remember now which one it was though. LOL.