The problem with it being just straight pr0n is that it's badly written pr0n. The words are clunky, the flow is terrible, and it really isn't written in a way that actually denotes feelings other than she is terrified of him. The BDSM aspects are rather on the vanilla side and even then, they do not follow the three main rules of any SANE couple that are part of the scene: aka SAFE, SANE, CONSENSUAL. Safe - the sub is the one who tells the dom what they want and the dom explains what they expect. Sane - the dom makes sure that the sub is okay with every aspect of the relationship before it is even started, and will take care of any emotional needs of the sub once the scene is over. Consensual - the sub agrees to the scene before it happens AND IS ALLOWED TO STOP IT IF IT GETS TOO MUCH.
In the first book alone, he pretty much expects her to live as part of a Total Power Exchange pairing. That means as his slave. He also breaks into her house and rapes her when she tells him that she isn't interested (which she plays off as being a joke), he tries to get her to sign a contract that is a SLAVE contract and not just a BDSM contract, he follows her across country, uses several illegal means to keep track of her and forces what he wants on her and gets mad when she tries to have a backbone. Half of the time, she submits to him because A- she is afraid of what he would do if she says no, and B- she thinks no one else will love her because she is 'so plain and ugly'.
Sorry, I do like smutty fluffy romances but to me, they are not that. They are not even bad it's good pieces of fluff. It's just two blank slates that just are not that interesting at all.