After reading Buckell's Crystal Rain a coupla years ago when Tor gave it away as a promo for the newly-released-in-paperback Ragamuffin and just-published Sly Mongoose, and liking it a lot, I finally got round to buying both Ragamuffin and Crystal Rain recently. While Ragamuffin is a sequel, it would also work very well as a stand-alone book. Someone reading it without having also read Crystal Rain won't get quite as much out of it and may miss some details, but would still enjoy it.
Where Crystal Rain was steampunk, Ragamuffin is space opera, chock full of splendidly heroic human freedom-fighterss, dastardly evil aliens (and their human minions), and lots of action. But it also has, like its predecessor, well-rounded people, and a consistent well-thought-out universe for them to inhabit. Definitely worth buying.