I was reading Jacqueline Carey's Kushiel's Dart for a long time, hence I've written about it twice before. It was my example for the appeal element language, and language, along with details, is one of the biggest aspects of appeal for this book. Carey evokes a different world with her careful, elegant, and distinctive sentence structure and vocab. The names of characters and places are so beautifully crafted I find myself at random times thinking the words without context for the mere sound of them in my head.
Much of the detail in the book is political-Monarchical intrigue and the history and characteristics of different lands and racelike groups in the book. I found this bogged down the beginning of the book--which is characterized by a distinct but short coming-of-age experience--but some readers may relish it, and the hard work early on pays off in consistent action and surprising turns later.
The character of Joscelin, an oath-sworn protecter of the main character, is established through detail, and his quiet, seemingly simple but surprisingly complex and human portrayal intrigued me and made me want to read books featuring mysterious but disciplined medieval types (I looked into Jeri Westerson's Veil of Lies: A Medieval Noir, but haven't read it yet). He has very specific repetitive actions and detailed, distinctive fighting and stance style and accoutrements. I didn't identify with the main character, Phedre, but her life story is epic--this definitely felt more to me like a plot-centered novel, though Phedre is a recurring series character.
Some additional notes on appeal:
Story line (e.g., genre, themes): fantasy, epic, saga, war, sex
Tone: foreboding, inquisitive, proud/loyal, exotic, sexy, dangerous
I won't even attempt readalikes because this is the first full-on fantasy novel I've read.