Shiloh always made more sense as a male name to me. Maybe because I grew up near a military base with the name. I don't see why it couldn't be unisex. I don't mind it so much on a male, there's something about it that makes me think of the Dust Bowl era and John Steinbeck novels. It's kind of a depressing name to me.
I saw a 20-something female Shiloh in a waiting room a few weeks ago, that was my first encounter with it on a real person, and it definitely felt strange to hear it. Somehow it works on a toddler, but on a young woman it was odd.