Admittedly, I am a Frank Herbert fanboy.
The Good: Frank is always good at the big concepts and all his trademarks are here. Focus on ecological impact, genetics, evolution of the human species. What's interesting here, as opposed to say the Dune Chronicles or the Dosadi Experiment, is the breeding/forced evolution is absolutely horrifying. I would go so far as to say this is Frank's horror novel. The breeding program and evolution of society is taken along the lines of insects, likely bees I would imagine. Thus, you get specialization and that's where the horrifying begins.
The Bad: It's a mystery that kicks into high gear with approximately 100 pages left. And that's the problem, the ending feels completely rushed. It could have easily been another 75-100 pages and I wouldn't have called it excessive.