I struggled to get into this novel, assuming it would transform from "Girl from colonized India struggles to fit into proper society" (a bit like the Secret Garden but with soirees) but instead, it took a quick left turn and became a glorious Horatio Hornblower riff, complete with gritty details of ship life. 
 The book suffers from two minor flaws. First, the authorial voice tries too "demmed" (or "d----d") hard to be cutesy and periodesque. Second, it is written quite politically as a lesson about anti-colonialism, both on Earth and Mars. This second bit bit into the story too much and was pretty heavy-handed, especially given the lack of honorable traits among any of the British and the ethical clarity of the Martians. 
 Despite that, the heroine has a grand adventure. The world building was delightful. The notion of the airships and the Napoleonic threats encountered felt fresh. (More than the His Majesty's Dragons, which I also enjoyed.) But this best part was limited to the middle of the book and the two bookends that began and ended the story didn't live up to that marvelous center. 
 I particularly hated the trope that (view spoiler)[the captain basically got injured (and later her brother) (hide spoiler)] so Arabella could take over the story. That's lazy writing. Her value and capabilities could have easily grown without the senseless (view spoiler)[mutiny (hide spoiler)] sequence. The French were a sufficient threat to carry the narrative without that. 
 In summary: the middle part (the majority of the book really) was really really good. The two end bits that set up the adventure and then create a silly distraction to eliminate (view spoiler)[the cousin (hide spoiler)] and force Arabella's hand (view spoiler)[in marriage (hide spoiler)] did the book no favors. Four Goodread stars for the middle, two for the start and end, and bonus star credit for the magic and wonder of inter-planetary air ships and automata, no matter how ridiculous they look. 
 Can't wait for the movie.