Kazuo Ishiguro's latest novel is much like Remains of the Day in that it murmurs gently along the currents of the narrator's memory and only gradually introduces the ugliness of the wider world. Ishiguro's greatest strengths are his smooth writing style and grasp of psychological truth, although I wonder now if any of his other works avoid a focus on bittersweet recollection and miscarried love.
This is not a book that revolves around plot, and although the revelation of the students' true nature comes relatively late in the book it lacks the capacity to shock; like the students themselves, we have been gradually prepared. The characterizations are strong but understated, and it's a testament to Ishiguro's skill that our pity and understanding of the characters overcomes any frustration that might otherwise naturally rise to the surface due to their flat incuriousness or irritating personalities.
It's almost a convention of the genre that clones must rebel against their fates and their oppression by the larger society, but Ishiguro's "donors" do not. Unlike Atwood's recent foray into SF/speculative fiction, this book uses futuristic themes to burrow deeply in search of personal and psychological truths. Whereas Oryx & Crake seemed content to pile hackneyed speculations atop one another with no sense that the ideas themselves were old hat, Never Let Me Go uses a single idea (the humanity of clones) as the basis for an ultimately psychological, not sociological, narrative.
This comparison brings me to the question of how to assess genre fiction which thinks it's not genre fiction (or, more accurately, which its author thinks is not genre fiction). Recently Terry Pratchett criticized J.K. Rowling for her assertion that she didn't know she was writing fantasy. Atwood's latest was called SF by some, but the author herself did not embrace the label.
For a dedicated fan of the science fiction and fantasy genres, it seems obvious that Rowling and Atwood were producing fantasy and SF and that their works can and should be compared to other genre works (although we can also compare them to other types of books; it's relevant to assess Atwood's writing relative to other literary fiction because that's the closest point of comparison in terms of prose style). It simply doesn't follow that "to claim an author's work for your genre, you've got to at least credit the author with knowing basic genre conventions." An author may unintentionally produce a genre work, but unless they've been raised by wolves their inadvertent generation of a pastiche of genre cliches is probably a function of their subconscious absorption of genre themes from the broader culture, or at minimum some form of parallel evolution in which the same end product independently arises from similar source material. The former cannot be called true creativity, and the latter lacks originality and must rely on other strengths as compensation lest it be a vague shadow of an older work. Elegant writing and finely drawn characterization can salvage what would otherwise be an unoriginal genre book and make it an outstanding piece of literary fiction. And Rowling, for example, is not a great writer, technically or stylistically; she lacks creativity and, apparently, sufficiently broad familiarity with children's fiction to even recognize the origins of her own works, but she is saved from obscurity by her surpassing skill with plot and pacing.
All this is just to say that Ishiguro has succeeded in using an old idea as the foundation for a well-written and perceptive book, and that even if it is not good SF (there's not enough speculative content to put it firmly in the SF category anyway), it is a fine novel.