The biggest continuity problems arose with a single book, as far as I know: The Masterharper of Pern. There's even a review of it somewhere around this site that points that out. As I've never read it...
Sorry, Ivy, I didn't get it right away what you wanted to say about fanfic authors in your first post. And I agree wholeheartedly. I have made the same experience in another fandom. We were/are fans of a TV series and there is one person who got to write a book with the series characters. I was sooo happy when I found in the local library and soooo disappointed when I found out that at least half the fanfic authors had better writing styles and better characterization. (And better story ideas)
