Unrelentingly dreary.

No, that's not quite accurate. Every few pages there is a sentence of considerable power (my favourite being "She thought maybe he lived in a kind of time that had no narrative quality") but for the most part, I didn't find the prose enjoyable. It reminded me a little of Lolita, actually, not in style or content or anything like that, but because it has the same quality of unremitting consistency, the droning of a single note. I did like the idea behind the story, but perhaps it's my own preference for speculative fiction that caused me to find the presentation of that idea so muted, so closed in on itself, that it stifled most of the potential wonder and horror it could have had.