Amazing. It's great both if you love Greek myths, and if you just like romantic stories. The characters are great, and very well written. Their interactions feel very real, and fun. You feel sorry for Demeter, and understand her struggle. Hades is both a strong, and weak in a very human way. You can really see him as a real person, not just a character. Persephone has a lovely transformation from innocent girl to powerful Queen in a very fluid way.
I really love that this is a story where the female character is very strong. She starts out very innocent, as many people start out in their first relationship, and you get to watch her become confident and independent. While the relationship is a big part of her, she is capable of standing on her own. It's clear the author knows how to write a good romance, because there is no uncomfortable power dynamic that leaves the heroine as just an object to tell the story. If anything it's her story about her finding herself, and the relationship is her way of gaining independence in a society where she'd have otherwise been losing it.
The sex scenes are really well written. There is nothing uncomfortable, or unnatural in the writing of them. The scenes help to tell the story, but remain entertaining to read.
I'd definitely recommend this book to anyone. It had me on the edge of my seat, and it's probably the first book I've ever finished without being able to read the ending first. It had me reading it the whole night, and the entire next day. I didn't set it down until I'd finished it, then I read it again. If the idea of sex scenes appeals to you, or at least doesn't turn you off to a book definitely read this.