I have to agree with rai on this one. It's success puzzled me. Perhaps I simply expected too much. As a huge Leiber fan, and knowing this was an award winner, I expected something to compare with the Faffhrd and Gray Mouser tales (my very favourite all-time fantasy, LOTR aside), or at least his Changewar stories (The Big Time etc), but instead it seemed to me this trod a lot of familiar ground that I'd read about and heard about too many times before.
I appreciate your points, jd, but of them all, consider only the 'character development' to have been especially well handled. The satire was heavy-handed, the adventure was predictable and the comments on society in general were done better by others elsewhere; first contact... I'm pretty sure that's been done before, just once or twice, and as for the inter-species sex...
Sorry, most of what Leiber wrote I truly relish, but this one really didn't do it for me.