The Maze Runner by James Dashner is not an easy book emotionally, because you know from the first page that someone is up to something experimenting with late children and early teens - and you don't know for sure if they have good or evil intentions.
It took a few pages, but not too many, for me to become attached to Thomas, to empathize with his confusion, anger, and fear. It also doesn't take very long for the world as it is first given to change in large and dramatic ways.
Maybe this is giving away too much, but the "Creators" are looking for young people who won't give up no matter what. That should tell you about the types of issues these children face, as well as how the odds are stacked.
I can't say I "enjoyed" it or "liked" it, but I'm interested enough in the story line and the characters to have grabbed the other books in the series. I want to find out what happens once the kids get back to the real world.
The other books in the series are The Scorch Trials and The Death Cure. There is also a prequel called The Kill Order.