My reviews are about my personal reaction to books, and although I recognise that this is a well written book, it just never rose above "liked it" for me. Which is what three stars means, so after dithering for a bit, three stars it gets. The dithering is that I think I've probably given four to things that weren't as well written as this. And there are many four and five star reviews of this on Goodreads and I agree with a lot of what's been said in those reviews. And yet...I still just liked it. So there you go.
If you've read some of the many other reviews you know what this one is about. I think the conceit (literary conceit, not character flaw) is clever, telling the story through the eyes of a not particularly thoughtful tween slave. Its a hard discipline, writing the story through the eyes of a blinkered character. I can admire the craft with which Emshwiller sticks to and works through that choice. I even enjoy it at times because the particular perspective gives access to some interesting insights.
But it also closes off access to others. We don't ever really get a chance to understand how the alien society or the society of the runaway humans functions because Charlie doesn't understand, or even really pay much attention to that. We don't really get to know or understand most of the other characters all that well because Charlie mostly cares about how things affect Charlie and is only barely beginning to emerge from that as the novel ends.
There's an odd flatness and distance for me in seeing that world through Charlie's perceptions. I feel shut out. Maybe that's a very clever way of putting the reader in the position of a Mount, only able to look at what Charlie is permitted to look at. But in the end it pushed me away from the story too much.
The clearest evidence of that is when I sat down to read this for one of my book clubs a couple of weeks ago, I got ten pages in and realized I had read it before. So even though I recognise the craft here, I ended up feeling so disengaged that I apparently forgot all about it within a couple years of reading it.
But many people really liked it, so I say pick it up judge for yourself.