Content warning A small spoiler.
Yancey's world is intriguing, and I found it rather difficult to put the book down. This was a pleasant surprise, since I hadn't actually planned on reading it; I didn't buy it, but it arrived in my home because it was a gift for someone.
Regardless, it's a much more interesting take on alien-takeover stories. It's refreshing because it's different. Aliens look like humans because they're implanted in humans; aliens don't look like what humans thought aliens would look like. Instead of the typical "aliens swoop down from outer space and kill us all with their ray guns" or Independence Day-style fights, this is more focused on guerrilla warfare and viewing humans as a pest. Literally as a pest. Cockroaches and slugs.
It's compelling, and there are multiple points of view; you're not just getting one point of view.
The only problem is that his character base isn't very diverse. It's a bit white. Even the one person "coded" as Asian isn't explicitly stated as being Asian (Ringer). And the coding is really basic and hyper-stereotypical: Super smart, likes chess, is a princess, straight dark hair, light skin. There's nothing else about her that 'codes' her as Asian, so it you're not even aware that she is until Book #2 (sorry, spoiler).