As many reviewers have noted, the original Rama is one of the true SF classics, where Clarke's powers shone at their brightest. No wonder that there is a devoted following to pick up new installments as and when they land on the bookshelves. The big ideas - suitably wrapped in mystery - have always been Clarke's forte, and so while he never intended for a sequel, it was clear that there was plenty to work with when Gentry Lee came knocking on his door. Wikipedia helpfully informs me that he wanted a more character-driven story, and I suspect that this, allied to his obvious interest and expertise in the nitty-gritty of technology seemed a good fit when it was time to unwrap the cylindrical mysteries. The problem of course is that a good lingering question, particularly of the why-are-we-here variety, is in itself often a very satisfying end to a good SF read. The sequels are, for good and bad, very different from their sire.
Now, story-wise and plot-wise, Rama Revealed is not bad. We get to see some pretty odd aliens at work and at leisure. There are moments of suspense (though we are not talking Hamilton quality here...), and there are interesting revelations. And of course, we are dealing with Rama, so the Clarkian overlord questions remain, and are eventually addressed.
But. There had to be a but, right, and a big honking whale of a but it is. As I said, Gentry Lee apparently wanted to provide a more character-based story, and the problem with characters is that they... talk. I hereby ungenerously submit that Gentry Lee is wholly unable to write dialogue. The things they say to one another! Have you ever found yourselves in a garden or forest, say, and heard, or even imagined, utterances like: "Look how perfectly trimmed all the bushes and trees are... They don't protrude one iota into the airspace above our heads." On every other page there is some statement to make you absolutely cringe. And this has, at least for this reviewer, devastating side effects. Human relations begin to feel robotic, jerking alive in an approximation of the real thing, when there is a lull in the mystery-driven plot. I seem to recall a text about Enid Blyton's work, wittily remarking that the characters seemed hell-bent on consuming lashings of Ginger Beer at every conceivable turn. The boredom of repetitive events is inescapably human, but that does not mean that revelling in mundande repetition infuses a novel and its characters with a sense of life. There is, to put it mildly, a lot of falling asleep and waking from sleep in this book. The walking around in tunnels, too, gets almost hypnotically tedious after a while, and unless you harbour a pathological interest in the advancing decrepitude between the ages of (say) thirty and sixty, the moaning about this issue ("We are not as young as we were..." etc.) gradually grows into a disproportion. The thing is that we probably would not even notice these narrative echoes if dialogue was alive and well, and was used properly to develop characters or advance the story. Then, even a lull in the story can be highly illuminating.
The flat and leaden characters detract so much from the story that I actually found it hard to finish the book, and I suspect that readers with even a nascent interest in narrative style will feel something similar. Without the great impetus provided by Clarke's rocket boosters in 1972: would anyone even be reading this novel? How many of the indulgently awarded rating stars here and elsewhere actually belong to Rendezvous with Rama rather than to this very much inferior postscript?