The last installment in the Silo trilogy is as good or better than the first one. Here we return to the main characters moving the story to a satisfying conclusion. This doesn't mean that there couldn't be any more Silo books. In fact it's really easy to continue the series in one of many different directions. But as an ending to the story arcs created in the earlier two books, it's a great closing.
As is usual in his books, the tension keeps rising until the very end where all the loose ends are well tied and you finish with a sense of satisfaction.
I have to admit that when I was reading the last pages I was having a sense of fulfillment like I haven't had in most books. This is officially one of my favorite trilogies of all time.
If you haven't read it, do it immediately.