This is a sequel to A Fire Upon the Deep; I don't think you have to have read AFUtD recently to understand The Children of the Sky--heaven knows I haven't--but having read it at some point will almost certainly help. There are all sorts of Vingean universe things that are sort of assumed, and if you've never read anything in this universe, that might get confusing.
I had two main problems with this book. One is that I felt it started slowly. The other is that it was full of squishy pink monkeys who were far less interesting than the Tines. I tend to call this The Atevi Problem: people who write aliens really well often make them more interesting to me than humans--and often write them better than they do humans, at least within a particular work. After the slow start, I found myself caught up in the intrapersonal dynamics of the Tines, but we had to keep dodging off to deal with squishy pink monkeys and their stuff. I wanted more of the Tropical refugees, more of Amdi, more of the fragments and their fates as politics shifted. And I got too much human nonsense, which I can read anywhere.
On the other hand, this is really one's only source for stories about the Tines, so something is better than nothing on that front.