Can't quite decide how to rate it - it feels like a better book than three stars, but on the other hand, I'm not sure I can say "really liked it" about it, so... three it is.
There were definitely things about it that I liked - fairly solid writing, survival story rather than one girl trying to take on the government or what not, relatively less-used scenario of the country running out of drinkable water (I never felt that was explained in a truly satisfactory way, though). Lynn's growing up was well done, and I liked how she didn't instantly change into mushy needs-protection girl the moment the love interest boy turned up - and I rather liked the way that love interest thing ended up, too; it felt fitting with the rest of the book and the way things happened.
Also, I liked Stebbs.
On the other hand, I guess I didn't feel the book quite measured up to the hype I'd been seeing before its release - it was a relatively standard, straightforward post-apocalyptic-ish survival story, all grim and stuff. Competent and interesting enough, but not groundbreaking or phenomenal - and while I liked the main characters well enough, I suspect that in a week I'll have forgotten all about them and their sufferings.