Otherland is brilliant because of the premise allowing all kinds of settings - there'll be loads more to come in the next three books. And I thought Renie Sulaweyo was one of the best female characters in any big fantasy epic.

Williams has a habit of being wordy, though, and that bothers some people. In the case of Otherland, you may find that some parts of books two and three drag, and the last book manages to drag its climax out across an impressive number of pages. I liked it, but some people might not. In addition, as Jens indicated (although I don't know if we're talking about the same thing), there's a plot twist in book four that's a bit silly.