The classic Herbert style shines through: very explicit separation of words and deeds from those thoughts that generate them; multiple levels of communication and meta communication; the amazing vision of the emergence of a new consciousness. All these are reappearing themes in his books: the transformation of Paul Atreides into Muad'Dib, the worm-man-god whose consciousness reaches back millennia trough his ancestors' memories and forward into the remote future through chains of possibilities shows a rather similar metamorphosis in the Dune series.
There is, however, one sentence, that I distinctly remember from the whole book (a mere 190 pages): "Isn't a man just a machine's way of making another machine?" An interesting twist of thought, a vague reflection on an old philosophical model (Plato's Allegory of the Cave in The Republic) on us not being able to perceive the world's true reality, our true nature and our own reason for existence.
Also notable: "The thing about computers-it's like training a dog. You have to be smarter than the dog. If you make a computer smarter than you are, that has to be accident, synergy, or divine intervention."
I am now looking forward to reading the rest of the series: The Jesus Incident, The Lazarus Effect, and The Ascension Factor (all out of print :( ).
The real strength of the book, though, is the constant narrative and ruminations on thoughts of artificial intelligence and consciousness (and fortunately Mr. Herbert only indulged himself with an expected but brief discussion of "consciousness-expanding" drugs in a subplot!)
Herbert does not complicate matters wilfully, but on the other hand he makes no concessions whatsoever to his readers' ignorance. He assumes that they are interested both in technology and in the problems of existence, consciousness and religion. There should be plenty of people like that out there, right? Maybe they are all too busy doing useful work to read SF novels!
The upside is that Herbert is a real expert, and even allowing for the 30 years that have elapsed (a huge chasm in terms of technical progress) this book is vastly superior to the schlock that passes for SF today. The Tin Egg has the authentic feel of an experimental interstellar spaceship, whereas starship Enterprise is basically a flying playpen.
As for the science, it isn't too clear just where the facts leave off and the fiction sets in - and that is good, too. Suffice it to say that we still aren't any closer to cracking artificial intelligence yet, let alone artificial consciousness. (See Heinlein's "The Moon is a Harsh Mistress" for another approach to the latter). So Herbert's speculations have hardly dated at all.
Personally, I rate "Destination: Void" as Herbert's best book, ahead of Dune, The Dragon in the Sea (Under Pressure), Dune Messiah, and The Dosadi Experiment. A matter of taste, I guess.
One of his favorite themes has always been consciousness, how we define it, what levels can be attained by humans, and is there something more that we're lacking. In "Destination: Void", the characters are forced to attempt the creation of artificial intelligence for their very survival, and all of these questions are called in to play, not to mention the ethical ramifications of their "playing God". Eventually they succeed in creating "Ship", and thereby set the basis for the entertaining, if bizarre Pandora series.
This is not the best book for someone hoping to read a story, but if you love Herbert and have an interest in philosophy, then he will take you on a great ride and share his perspective with you in "Destination: Void".