I read Crystal Soldier a few years ago, right after it came out. I'd forgotten some details, so I re-read it before starting Crystal Dragon. CS was good, but CD was marvelous. I can't do it justice, but if you've read anything set in the Liaden Universe, you want to read these. If you haven't, they're a lovely place to start. Despite the fact that I knew one thing had to happen, I cried. There are very few books that get to me on that level.
The whole series is science fiction with a nice touch of romance. They don't get mushy, and this duology in particular is far from "soft," but the relationships feel right. There are some fantasy elements that disallow a "hard SF" label, but that's fine. They never claimed to be hard science fiction.
Now I hope to get hold of both volumes of the Liaden Universe Companion. I have all but the last two chapbooks, so I think I have all the stories, but it would be nice to have them all together.