Actually quite enjoyed this one. Not only did the characters get to return to the city of Ember, but they got to recover a lot of their stuff, and tie up loose ends. This book answered a lot of questions, and wrapped the series up well enough that I get the impression no more stories will be written for this series. But there is no need. It was wrapped up satisfactorily and people resumed their lives.
All in all a good fun read of a future that will never be. Thank God! :)