It's tough to review this book, I have read the entire Black Jewels series and so my opinion of this first book is coloured by my thoughts on the entire series.
There is definitely some major content warnings that readers need to be aware of ahead of time, and I think that they are somewhat reflective of the time it was written (late 90's) - not to say that rape, sexual assualt, and paedophilia weren't a big deal at the time, but that writers weren't as aware of how problematic including those topics in their books could be.
I definitely wouldn't recommend this to anyone under 18 to read, and would make sure to warn anyone that there are some quite graphic descriptions included, I definitely skip over those sections when I reread. 
Getting past all that, the basic story is really interesting and the characters are wonderful, especially as you move in to the next 2 books and beyond (one of my favourite characters is introduced in book 2 - kiss kiss!). I think that Jaenelle & Daemon's relationship is actually the least interesting/likeable, and is somewhat problematic, but the rest are fantastic.