I admit, the first third or so of this book was hard to get through. There were several reasons for that: a story told by a 15-year-old girl, written the way a 15-year-old girl might write it, is all very good for realism, but it also means having to read a story that sounds like it's written by a 15-year-old. This is hard if you're not fifteen yourself.
Also, this particular 15-year-old was not someone I could relate to at all. I've been fifteen once; in fact, I was fifteen at a time when there was an actual worry and possibility of war breaking out, and, well, let's just say that I was focused on other things than having sex with my 14-year-old first cousin. So was every single other 15-year-old I knew at the time. So, yeah. I had a really hard time relating to Daisy or liking her.
(Also? I know that relations between first cousins are legal and not always considered incestuous, depending on the country, traditions etc. I'm actually fine with the idea under some circumstances. But in this case, Daisy kept pointing out how it was incest and how they shouldn't have been doing that, and Edmond was only 14 (and I didn't like Edmond at all - I get that he was supposed to be all mysterious and cool with his smoking and telepathy or whatever that was, but, well, no, he was just annoying and incredibly two-dimensional), and all this added to my ick factor.)
That said, it got considerably better after Daisy was sent off with Piper. Sure, John Marsden did the whole "teenagers in a war situation" much better in his Tomorrow series, but still. At least there were no irritating little boys smoking and having sex with their spoiled teenage first cousins.
The very ending... well, I get the point of it, but it jarred. There were no real explanations offered, apart from "Daisy's father had connections", and... eh. Also, again to draw a parallel with the Tomorrow series, while there I could suspend my disbelief enough and believe that the occupiers were unknown (because the attacks came out of the blue and the main characters were already cut off from others), in this one, it actually bothered me. Even the most shallow and uninterested teenager should have had some idea of who "the enemy" was, surely, if people had been fearing the war for years?! (Never mind that if people had been fearing a war breaking out for years, I find it hard to believe that a country in risk of attack would blithely send off most their forces to foreign territories and not prepare for an attack. Whatever, I suppose.)
Now, after finishing it, I suppose I didn't end up entirely hating the book, largely because the middle third was actually interesting and decently written, especially once I got used to the whole "sounding like a 15-year-old" writing and random capitalisation and lack of dialogue punctuation. And I don't entirely regret reading it. Also, at least it was short. Would I recommend it, though? I'd have to say no, absolutely not, although I'm quite sure many people do/will enjoy it.