The Long Way to a Small, Angry Planet is easily one of the most feel-good books I've read in a while. Put it this way: I think if Kaylee decided to rewrite a cross between Firefly and TNG, this book might be the result. There really aren't any bad guys; just people with problems, each of which is bound to find a solution. It may not be so good for general YA--lots of of profanity, and given that one of the species involved is prone to orgies, there's also quite a bit of sexual content-- which is unfortunate, since in all other aspects, I think it would have been good for a younger audience as well.
As in most space-opera-style scifi, there's lots of political and social commentary, mostly in a positive social-uplifting way. Mind you; I think a lot of the scenes and the characters' actions imply a much more problematic perspective, which may be one reason I couldn't totally jump onboard with the story.
Whatever my feelings about certain subplots, I was extremely impressed by the way Chambers managed to keep everything fluffy and positive without ever drifting into the saccharine. If you want a low-key heartwarming read,The Long Way to a Small, Angry Planet is definitely worth a look.