Everyone in a story has a story. I really don't think there is a generic best answer to this question, not absolutely, and not even usually. There are too many things for readers to get out of these stories to say that there's a default viewpoint.
Our genre here is an oddball one from a story-telling perspective. It has one or more main characters that often has absolutely no agency of her own. This is a big no-no in writing, having characters be entirely reactive, but in ravishment stories not only can the victim be entirely reactive, the reaction might be nothing more than expressing grave distress, not actually doing anything on her own. I mean, we can have perfectly good stories where the victim is rendered immobile and voiceless before she gets to say or do anything. She can start and end bound, blindfolded, and gagged in a basement and it can still be a perfectly valid story whether told from the rapist's point of view or from her own. It's a known and accepted convention in this genre that a story based entirely on a stream of negative emotions is a normal thing. It doesn't have to be, but it can be.
So the best answer, I think, is that when you, the writer, are trying to pick the POV, just ask yourself what you are feeling as you set down to create? If you want to focus on her fear, her shame, her pain, her confusion and distress as her world is shattered, then go with the victim POV. If you want events leading up to the story to be murky, unexplained or inexplicable, go with the victim. If you're getting off by mind-reading a raped woman's thoughts as she is brutalized, go with the victim. But on the other hand, if you want to emphasize why she has it coming to her, over some past offense, go with the attacker. If the thrill is the hunt, go with the attacker. If a misogynist stream-of-thought accompanies the actions, use the attacker. It really can go either way.
Personally, I don't and wouldn't worry about how well your own viewpoint meshes with the story POV. Authors here and everywhere vary in their level of attempted realism, and rape stories are rarely written without the express purpose to titillate the receptive reader. In my own writing, though I try to really mix it up in terms of POV, first vs third person, etc, I fully realize that my stories rarely are all that realistic. They're usually some high-concept idea I got in my head and frequently include a healthy bit of absurdism, satire, surrealism, or just go full-out into speculative fiction. I'm happy with suspension of disbelief in my readers, but I'm not going to create the perfect rendering of the real raped woman any more than I can define a real rapist because I don't know either of those things in real life. I can write realistically about middle-aged, middle-class white men sitting at computers mansplaining sex and writing. Everything else is creative writing. As long is the story mimics life enough to get a rise out of the reader or (insert female equivalent metaphor here), you've done your job well.
