It really pissed me off. I spent the first two books kind of liking the main character, who always tried to do what was right or at least would not hurt people. But towards the end of this book she makes a very stupid design that didn't not fit with her character and in general it was a very stupid idea, that could not work. It wasn't even a interesting stupid that I want to watch and see what happens. Instead I spent the last part of the book skimming.
Honestly I'm not sure if I'm going to read the 4th book because this one had me so mad, but I might read the 5th for the back story.