I'm really into classics, and I'm especially into genre classics, so I almost feel a little bit guilty giving this book a "mere" three stars (although I feel I should note that I actually use the Goodreads star values, in which a three-star rating means "I liked it"). Ultimately though, I feel I have to rate and review books honestly, for my own piece of mind if for no other reason. I liked this book, but I don't feel much stronger about it than that.
Stand On Zanzibar has a lot of things going for it. I enjoyed a number of the characters (especially the smart-ass sociologist Chad Mulligan) , and I was really interested in Donald Hogan's storyline in particular. A number of Brunner's predictions about 2010 were eerily prescient (he nailed the global population, if not the effects of said population) , and even his predictions that weren't accurate still made a lot of sense when viewed through the lens of the 1960's and the geo-political climate of the Vietnam and Cold wars. I'm not one of those who gets really critical when a SF author predicts something incorrectly; as long as the story can stand on its own, I'll appreciate it for what it is.
The main beef I have with this novel regards the style in which it's told, which is something which is so integral to the novel that one can't review the book without mentioning it. For those who haven't read the book, Brunner basically borrows a style from one John Dos Passos (apparently, although I've never actually read Dos Passos) wherein regular plot-driven chapters are interspersed with chapters about characters who have nothing to do with the main plot and only serve to give the reader more information about the world. Further, there are also a number of chapters that have no plot at all, but which contain a selection of cultural samples (soundbites, basically) arranged in such a fashion that they're meant to convey to the reader a larger sense societal currents. Some reviewers seem to think it brilliant and some hated it. Personally, I found that there were some chapters in which it worked (for example, I enjoyed the party scene, which is told entirely in snippets of randomly overheard conversations) and quite a few where it didn't (one of the worst was the description of the music video which was not only completely irrelevant but also nearly nonsensical). The chapters where this style didn't work were quite numerous, and as a result I found myself having to wade through a lot of what I considered to be filler to get back to the main threads which I had been enjoying. The book, in my opinion, could easily have been 100-200 pages shorter and not suffered for it at all.
As a closing note, I'll point out something else which bothered me and tended to take me out of the story from time to time, although not nearly to the extent that the fractured narrative did. This was Brunner's invented "futuristic" jargon, which is something attempted by many SF authors, and which in my experience is almost always a bad move. Although rare and difficult to pull off, an author can correctly predict some world events or technological achievements. It is nearly impossible, however, for anyone to predict the vagaries of the vernacular, and I think it's not only a waste of time but also tends to make dialogue written in such contrived slangs sound pretty silly.