Spoilers
While this final book is more well-written than the third book, I found myself very underwhelmed and confused.
There were many themes that seemed to come out of nowhere but that should have been woven in from the beginning. The obvious lack of Watcher left a big hole in the heart of the story (she's my favorite character and I missed her greatly!!) and even bringing Connie back couldn't make up for it, because this Connie is vastly different from the Connie of the first book.
While I was pleased that Connie wound up being the betrothed, the whole marriage plot was a little weird to me. I must admit I shipped Watcher and Owen from the beginning and absolutely adored Connie and Owen's relationship. But once everything was revealed, you never got a real sense of their relationship. It was just, This is what's going to happen and that's that. Nothing was really developed. Connie in particular is hardly seen interacting with Owen and yet once she's told she's going to marry him, she's suddenly madly in love with him? I mean, I totally believe she had a massive crush on him in the first book, but that seems to be a leap.
There's also the age thing that bugs me. How much time is supposed to have passed since the first book? Owen is described as being at least two years behind the other freshman at his school, so he's at most thirteen? Connie I believe is younger than that. By this book, Clara, who is a few years older than Owen, is still in high school. So Owen and Connie get married as teenagers?
I personally think that this series could have been pared down and written as a trilogy, focusing more on weaving in the many themes of the story so they don't just seem to appear out of nowhere. It almost felt like the authors were making up the plot as they went. Also the various relationships needed to be fleshed out more. Connie's in the first book, you fall in love with her, then she disappears, we meet Watcher, fall in love with her, then she dies and now we're back to Connie. It all just feels very disjointed.
Ultimately there's nothing wrong with this series. If a kid asked me if they should read them, I'd say go for it! But I personally wanted more.
As a whole, I loved three of the five stories, but this final story left me wanting. (And believe me, I WANTED to like it. I desperately TRIED to like it, but I just couldn't.) Had I read this series as a kid, I may have not cared as much, but I can't help being disappointed cause it should have been so much better.