I liked the Zelazny book that I reviewed previously a lot, despite it being confusing and not particularly well plotted - all down to the quality of the writing which was just beautiful. This is better. The writing is still as good, but the plot is clearer and the whole work is just so much less confusing and hangs together better. Mind you, the overall impression is, four days after finishing reading it, one of "wow that was good", but I'm buggered if I can remember what it was actually about!
Forward was first of all a physicist, and only secondly a writer of fiction. His fiction tends towards the scientifically plausible, without much in the way of "God Tech", and his better works are characterised by, errm, good characterisation. The people on his pages really are people, with lives, conflicts, desires and so on. That holds true for this work too, with a few minor exceptions. The characters are generally believable, even if those who stay "off screen" and are only talked about are somewhat one-dimensional - but that can easily be ascribed to the speakers' bias and limited knowledge. After all, plenty of us can't truly describe our bosses as fully-rounded people. The technology and science used is also believable. However, that's only that which is used. That which is inherent in the people (and I do hope you'll forgive me for being somewhat vague - being too specific would give away the "reveal" at the end of Forward's magic trick) is, at least in two respects, rather implausible. But this doesn't really take anything away from what is overall a good story, told well, by a skilled author.
I recommend it. If there were to be a sequel following the surviving character's new career at the end, I'd buy that too. And that, my friends, that wanting to read more, is the sign of a damned fine book.