"Rebellion" is a well-written adventure book with a strong female lead. It is classified as fantasy, since the story takes place in an alternative world with quasi-medieval weaponry, houses, ships, and other aspects of people's livelihood. On the other hand, the empire of Charanthe is more orderly than a typical fantasy empire. For example, all children are taken from their parents as babies and raised in schools, where their skills and attitudes are constantly observed in order to determine the best future job for everyone. Initially I was under the impression that "Rebellion" was a science fiction story, since such surveillance is more common in fictional societies with the technological means to secure it -- but that was before the sailing ships and other fantasy elements appeared.
Eleanor is a strong character and many of her adventures are fun to read. The story is not always what it seems to be, and does not always go where the reader would expect it to go. The author has a few surprises up her sleeve, so the story is never boring. Besides, Rachel is a very good word-crafter. She has a knack for creating scenes that make her reader feel as if he or she is inside the story instead of reading it.
A word of warning, though (and a minor spoiler alert): not all of Eleanor's adventures are fun. There is a detailed torture sequence in this book. Also, the heroine, while likable because of her resourcefulness and strong character, is not likable in other aspects. Sometimes she is too headstrong and egoistical. She can also kill, steal, and cheat without giving it too much thought. This is a fantasy book about assassins, and characters who are neither "good" nor "bad" can be interesting, but still I would have preferred Eleanor to question her own deeds, together with their rightness, wrongness, or worthiness more often and more closely. Eleanor has potential, so I am expecting her to grow out of the "it is all right to do anything because I want something" attitude in later books.
I very much appreciated the way the author approached gender in this book. Except where she hinted of romance, she treated both women and men (or rather, girls and boys, since most of the important characters are young) as just people. She did not focus on their gender. The characters had personalities, dreams, skills, flaws, redeeming qualities -- all of this as people, rather than women or men. This is a breath of fresh air compared to some fantasy books where the authors present their characters as led predominantly by their biology.
I am looking forward to reading "Revolution," which is the next in the series.