Having watched the film first, I knew more or less the sequence of events and more importantly, the ending, which still doesn't satisfy me.
It was hard for me to connect with Thomas as a main character because of his "curiosity". I was overwhelmed with his non-stop questioning. I'm glad a few characters pointed that out but I'd have appreciated it more if the author had edited him a bit. Also, his relationship with Teresa felt really forced to me.
That being said, the other characters were quite fun to read, especially Minho, and there was plenty of action to keep me hooked.
I don't feel like I need to read the other books ASAP, despite the cliffhanger, but I will continue the trilogy in the future.