I really got into it for about the first half and then I just lost interest as the story progressed. I think what did (or didn't) do it for me was the fact I never really cared that much for Mary and certainly didn't see what both guys saw in her. Also, I can take unanswered questions but by the end of the book there were too many for me. Why didn't anyone ever write anything down so the towns had history? Why didn't Mary and Travis talk about all those unresolved things sooner? Why didn't they plan an escape from the house from the beginning? It just seemed illogical to me. And I know there wouldn't be a story if the main character in a first person narrative died... but there were one too many close calls (and too many people dieing for her) for me to cheer for Mary's escapes. I just became disgusted.
I doubt I'll read the sequel.