Kushiel's Dart, obviously leaving out the political/religious prostitution aspect, is pretty spot on when it comes to the bdsm scenes. The submissive is respected for her abilities, so are the dominants. Everything is discussed beforehand, with the understanding that either can call a halt at any time. Limits are set, scenes are discussed, all before anything happens.
Her first dominant slowly trains her and introduces her to the tools of the trade. She is reminded over and over again not to go too far, not to ask for more than she can handle. Even the dominants that really want to test her limits, because of her god mark, respect that she is inexperienced. So they slowly build up the experience. They make sure she is in the proper headspace before proceeding further. They don't just start wailing on her with a belt right out of the gate.
In the scene where Phèdre doesn't use her safety word and she gets seriously hurt, her dominant freaks and her master chastises her, really spot on. The dominants have to trust the submissive to know their limits. Her reputation takes a bit of a hit due to that, as does the doms. Having to call in the medics is a sign that someone, in this case both of them, messed up. And the dom takes care of her and helps her. He doesn't let her stumble off to cry by herself.
The bdsm scenes and the description of the urges and how they feel is fairly accurate. It's about trust, pushing your limits, learning yourself, and the rush you only get when that pleasure/pain threshold is reached. Like Felicia says, it's a great book. Everyone should read it. It's not a romance though, there is some gore and lots of fighting. Just a fair warning.