At first, Without Mercy reminded me of Alex Rider's Point Blanc. That's mostly due to the blurb, which talks about a elite school for troubled kids. But it's not. And I have to say, I'm not very impressed with the Lisa Jackson books right now.
It feels as though she's pushing an agenda: She doesn't seem to have a good view of Christianity. Well, if you think so, ok. But why spoil a book with it? It's alienating a lot of readers, not just Christians. To make matters worse, Christianity had no bearing whatsoever on the plot.
And believe me when I say, the only redeeming feature of the book is it's plot. Mong read a section of the book and started laughing, due to the way it's written. And I have to admit, it's not very good. It reads like how I would write, and I'm a terrible writer :/ For instance, I have no ounce of poetry in me (It took very long, but I finally learnt how to appreciate poetry, although I still cannot understand Wole Soyinka). Which means unlike other writers, who can make their prose sound like poetry, I cannot do anything like that. Boring isn't it?
Like I said, the plot redeems the book. The premise of the book is interesting, and the plot is rather well-developed. I thought the characters were fairly well developed, except for one main character. The sudden (and I felt, unnecessary) plot twist made the characterisation painfully shallow, because unlike Emma, when I flipped through the book a second time, I could see no hints of what is to come.
Honestly, you should only read this book if you're very bored. The themes in the book aren't very good, and the writing is only average.