There is something to be said about book covers... I know you are not supposed to judge the contents of a book by its cover, but these are just so pretty!!! And in this case, the books do live up to the expectations. I literally flew through the first two books, and had to really pace myself while reading the third one because I did not want to leave the world created by Bardugo. These are a real treat for fantasy lovers. Unlike most high fantasy books that loosely base their world on Medieval Europe, Bardugo got her inspiration from Russian/Eastern European medieval culture and folklore.
My review below does not contain any spoilers, as I believe it is better to go into these books blind. The only thing I'd like to say is that Book 3 of the trilogy is by far my favorite in the series. In the first book, readers (along with the main character Alina) are confused by their feelings for the Darkling. He is powerful, mysterious, impossibly attractive, but also so very bad.... Some of us were hoping he wasn't really bad, and would at any minute turn into a good hero... Alas, never happened. In the second book, as Alina learns to master her power, she is still not sure of herself or her destiny. She is surrounded by three men vying for her love, and the one she really wants feels he has to give her up. Reading the second book, I still was not sure where Bardugo was going with the plot and what she had in store for Alina. The third book made all things clear and brought the story to a wonderful conclusion. I could not be happier with the way the story ended.
I am not going to comment on all the Slavic references "gone wrong" in this book. This is not historical fiction. It is a fantasy that loosely integrates bits and pieces of Eastern Slavic language and culture into the story. I thought Bardugo did a wonderful job with that and created a unique world that I loved immersing myself in. Enjoy the trilogy - I highly recommend it!