I have no idea what it was like originally, but the current version has no vampires or reference to anything Twilight-y. I wouldn't know if it weren't for the news that it started as fanfic.
I started reading it because of the Dr. Drew controversy and while at first I thought he was being way too judgmental, I have to say I kind of get his point. I'm not judging whether this is a "healthy" fantasy - what does that even mean?? - but it's *not* your typical strong-dominant-male romance scenario. The chick is a virgin, and her first introduction to sex is through a BDSM relationship with a guy who only likes BDSM because of his extraordinarily messed up childhood and who can't stand to be touched.
I don't know anything about BDSM so I can't speak to any authenticity issues there, but in terms of men "in control," I love a dominant hero as much as the next suburban housewife, but this one rings false for me. I think it's because the heroine is so inexperienced and unsure of herself. There are places where it smacks of abuse to me, where she really isn't happy with the arrangement. Her emotional needs aren't being met, and she's only doing the physical stuff because it pleases him, not because it pleases her. (She still has lots of orgasms, though. One of those pleasure-in-spite-of-herself scenarios.)
I think that's supposed to turn into an emotional healing thing but I haven't gotten there yet. I may not, because the writing is... meh.
Everything I've read is legal and technically consensual and I'm not trying to pass judgment. This was just what I think people might want to know about the book before they read it, if they aren't sure whether it's up their alley.
Hope that helps.
P.S. Apologies if this is the wrong thread. It looked like the other one was discussing more fanfiction/copyright issues but I didn't read the whole thing.