IMO their neither and yet both. Their physical strength comes from mechanical enhancement, but they have biological parts as well.
Some of them even don't know that they are replicans, like Rachel. This is also valid for Deckard. I'm glad the filmmakers leave that point open for interpretation...
I saw Blade Runner for the first time on DVD, never saw it in the theaters or on TV. And I found it very fascinating from the start, later I began to love it.
I saw the trailer today at the movies, when I was going to see ATOMIC BLONDE.
I can't say that I liked it. It didn't breathe atmosphere of the original.