Yeah, fanfic characterizations can vary wildly. I think one of the most traumatizing Spike fanfic experiences I ever had was a fic that was beautifully well written but that I hated! And I think one of the reasons I hated it so much was that I could see it as 'in character'... if you had that take on the character. It wasn't "my Spike" but it was a convincing interpretation of canon Spike... just in totally contradiction to the one in my head. Because it was convincing, because it was a logical interpretation, and because it was well written, it bothered me -- a lot. More than if it has simply been junk.