I'll hold off rating this one until I think about it a bit... there is a lot to like about it; but a lot I just didn't understand. My elevator sometimes doesn't go all the way to the top.
Here's the thing: at another time and place, I would probably rate this a 4. However, in this current time and place, the complexity of the structure, an allegory that I never really "got" and the flat affect of the central character all kept me at arm's length when what I wanted, most, was to be immersed in a story. I admire this in the same way I do an elegant five-course meal, but what I was looking for was more mac-and-cheese. The fundamental premise has an absurdity to it that I normally respond to, and there are sections of prose that truly elevated (ha) the thing to 4-star levels.
I stand by my last status update comment which is that my sense is that this was trying to be too many things at once and for me, it just didn't come together -- or rather, I didn't have the brain power and focus to bring it together. In particular, the allegory seemed to be interpretable (is that a word?) in at least four different ways. And was it supposed to be a literal portrayal - or a purely conceptual one? If the former, it's muddled. If the latter, it's too remote to involve me emotionally. If both, I just don't have the ability to manage the relationship between figure/ground that is required for the thing to work.
It's about race, yes, sure, or so we're told. I mean, that seems obvious. But it's also about all kinds of other black/white societal structures - class, religion, gender, politics. And when something can be everything, then it ends up being nothing.
And then we have this big concept thing wrapped around a noir-like "mystery" that wasn't very mysterious (not to mention, not very dramatic. I can anthropomorphize a lot of things - I've been known to cry at the IKEA commercial when the desk lamp is set out by the curb in the rain. But I couldn't get there with these "elevators.")
So between all that, and the fact that Lila Mae Watson was such a cold fish, it left me feeling a bit m'eh. Definitely required more attention than I was able to give it, so I net out at a 2.5ish.