While I agree with the previous reviewer that this collection is uneven and even a 'hodge-podge,' I didn't find that to be such a bad thing. True, it's not a collection of classic sci-fi stories, as the dust jacket may make it seem--but the wide variety of stories makes the collection enjoyably unpredictable, avoiding the repetitiveness that plagues some collections of science fiction. I first read this anthology in elementary school, and found a couple of its stories so entrancing that I have continued to check it out from time to time just to reread those stories.
In my opinion, it's worth tracking down a copy of this book just for the story "The Web Dancer," which is incredibly beautiful and sad and has had an enormous influence on me. The fact that it also contains "And Who Would Pity A Swan?," "The Hob," the title story, and the story about glaciers whose title I don't remember makes it even more worthwhile. Certainly there are a few poorly constructed or just plain bad stories, as pointed out by the other reviewer, but their presence doesn't destroy or dominate the anthology to such an extent as to make it not worth reading.
Besides, someone connected with my high school gave this book a good review. How can I disagree?