I've been a fan of Orson Scott Card's Ender series for quite a while now, and I recently read the fourth (and last) book of the spin-off Shadow series which focus on Ender's lieutenant from Ender's Game: Bean. All eight books are certainly worth reading, but at this point I hope that Card lets the series go.
To star off with, let me recap my opinions of the seven books previous to Shadow of the Giant. Ender's Game is absolutely brilliant. It is one of those books that should be required reading, whether you like science fiction or not. It's one of the best depictions of the thoughts and actions of children (albeit extremely brilliant children) that has ever been put to paper. The other three Ender books (Speaker for the Dead, Xenocide, and Children of the Mind ) are very different from the first. They're interesting, although I think that Card let the things that he was trying to say about the Philotic Web and the connection between all living creatures got in the way of what should have been his primary purpose; that is, telling a good story. Ender's Shadow is hard to judge on it's own. It's more of a sidebar to Ender's Game than it is a standalone novel, just explaining everything that Ender's lieutenant Bean was doing during the events of the first book. I found it a fun read, but, in the end, I thought it was kind of pointless. However, things picked up with Shadow of the Hegemon. I really enjoyed that book. It involves Bean joining forces with Ender's brother, Peter, and how the two of them struggle to unite the world under one government. I thought it was a very fun and interesting take on geo-political wars. On the other hand, Shadow Puppets went back to Card's preachy, philosophical ways. They didn't get in the way of the story as much as they did in the latter Ender books, but when you have a whole chapter devoted to explaining that the purpose of life is to have as many children as possible, that's really going overboard.
That brings us to the last book of the series, Shadow of the Giant. The books picks up right where Shadow Puppets left off, both in terms of story and philosophy. However, it didn't bother me quite as much this time around. This is probably because there was quite a bit more of the geo-political machinations from Shadow of the Hegemon than there were in Shadow Puppets. (Although, if our leaders would only realize that they shouldn't be so concerned with power because making babies is what's really important, then the world would be a much better place. . . .). In the end, I felt that Bean and Peter's stories were drawn to a satisfactory close. Card did leave some loose ends dangling at the end of the book, but I just don't know how many more interesting stories can be told from that world and would be satisfied if he just let it end here.