I'm probably misusing the term, but this book is awesome in an old-fashioned sci-fi way, and it reminds me (unreasonably) of the Vorkosigan Saga, which brings the term to mind. But space opera is sweeping and epic--so far, Devi's story only hints at the Big Politics out there.
Backing up: Fortune's Pawn, by Rachel Bach is so great I want to squee. I swallowed the thing in just a couple of bites. Like I said, there aren't a lot of ways in which it is actually like the Miles books, except for that feeling I get when I'm reading them. That sort of awesomely competent character in over their head but about to come out on top.
Devi Morris is a mercenary from the world Paradox, and a damned good one. In fact, she's risen about as high as she can go in her outfit, and has her eyes on the elite Devestator squad. But they don't take you without years of experience--or a few months on a crazy, high-risk ship like The Glorious Fool. So Devi packs her Iron Man-style armor and saddles up to make her name.
There she meets Rupert, the mysterious and sexy cook; Cotter, her meatheaded fellow security officer; Basil, the snooty navigator from an avian race; Nova, a sweet, dreamy girl whose kooky religion may actually give her powers; Hyrek, the ship's doctor, whose lizard-like alien race literally eats humans for breakfast; and Ren, the captain's strange, blank-faced daughter. This ensemble cast is why you will love this book--Hyrek has a wicked sense of humor, even though Devi's first instinct is to kill him. Basil is a complete snob, but he is paternally protective of Nova, who becomes a good friend to Devi.
And then there's Rupert. After an initial urge to bed him, Devi realizes there's more to him than meets the eye, and she can't figure out if that's a good thing or a bad thing. As they get closer and Devi fights off the first of a really remarkable number of attacks on the ship, she realizes that there's more going on here than meets the eye.
I will admit that this book is mostly setup. There's a lot of mystery, and a good deal of it gets explained at the end, but you wouldn't call the end of this book "closure." I mean, it ends--it's not a cliffhanger--but if the sequel wasn't out there waiting for you, you might be annoyed.
I don't know if I can explain what I liked about this. I loved the world building. I loved Devi. I loved that she started right out trying to get Rupert into bed, but then backed off when she realized he was something more than a simple cook. I loved the ragtag crew (and yes, the Firefly comparisons others have made are apt--loveable! I love them!). I loved the immediate sense of trust I felt--again, Vorkosigan-like, I knew that my protagonist was good at her job, and I would not have to rely on her doing anything stupid (or at least not the kind of stupid that people do just to move the plot of a novel along).
I can't explain it. It's just really, really, REALLY good. Thumbs all the way up.