Peeps, the predecessor to The Last Days, is one of my favourite vampire novels, and definitely my favourite young adult vampire novel (yes, I'm looking at you, Twilight). Vampirism as a virus created as an evolutionary defense against a bigger predator? Brilliant.
...The Last Days is a huge disappointment after Peeps and my least favourite of any Scott Westerfeld book I've read. In Peeps, Cal, a lovable Southern boy, has to hunt down his ex-girlfriends because he's a carrier for vampirism. He didn't know that and unwittingly infected all of his ladyfriends. Westerfeld gives scientific reasons for all of the vampire stereotypes--love of garlic, fear of crosses, et cetera. It's good fun.
In the sequel, most of the book is about a group of teenagers who decide to start a band, and a crazy vampire is their lead singer. Most of the book is the squabbles they have amongst themselves. It's very juvenile and very boring. As I was reading, I had no idea why I should care. Vampirism is growing more widespread, but the teenagers are too caught up in their own little melodrama to pay it much mind. Finally, near the end, Cal comes into the picture and things grow interesting again, but that's the last 100 pages of the book.
If you loved Peeps, I'd just stop there and not bother reading this one. And if you haven't read Peeps, go and read it.