My angel/slug poll was not take by vast numbers of people, but still there's a trend. The lexical view wins. All the angels before any of the slugs--but do ( ye gods) create some slugs. They have some value.
Tim Mulgan's book Future People) is that the A-humans can autonomously choose between independently valuable options. They can think through their own decisions in life, going this way rather than that for their own reasons. The B-humans cannot, but their lives are still worth living. They are not like Cs, who may as well not be born at all.
Sci-fi upshot of his view: a people factory, run 100% rationally, would manufacture all A's if possible, but some Bs, if it ran out of critical parts for the As. ("Darn, we ran out of that autonomy chip! Oh well, lets make some people without it.") And no Cs.
More about that another day. There is much that is puzzling and problematic about this picture.