I haven't yet read 'Fire upon the Deep', so I can't compare this to it, but it is certainly up there with the best full-on space operas I have ever read, e.g. Dune, The Mote In God's Eye, the Gap series. All the criticisms you can read below are true, but in fact 'Deepness' is such a strong story that it isn't brought down by any of them. Vinge drops bombshell revelations and insights to the reader far more regularly than you would think possible for such a long book. Ultimately all the tension he builds over hundreds of pages is released in one of the most wickedly scripted finales ever, with the details of every one of the huge cast of characters coming to bear on the outcome. 'Deepness' is unashamedly romantic in places but Vinge does horror just as well as fairy tale fantasy so it ends up well balanced enough. A few plot holes are just as easily forgiven. Don't miss this.