"A Saucer of Loneliness" is one of two stories most important in making SF considered a "serious" field (the other being RAH's "Stranger"). Of the two, this certainly isn't the better, but it had more of an effect on me, personally. The end notes in this book note that it talked Spider Robinson, one current major SF writer, out of suicide, and it has more of an emotional effect that that could explain.
The rest of the book is still amazing. The second story has an interesting idea, but sloppy execution. The following, "The World Well Lost," literally made me fall out of my chair laughing, and includes the RS drive, which might be the most creative invention I've seen in years. Much farther on, with "The Clinic," you see the same type of emotional depth as you did in "Saucer," presented almost as well. Any one of those stories alone is worth the price of the novel.
For continuing fun after you've read it two or three times, I occasionally repeat parts of the "Koala" conversation out of "Wages of Synergy" without context. It makes my day to break up a serious revelation with "Koala..." "What does that mean?" "It means a great deal..."