Straight up - I loved this story because in it, a big guy got some loving. I'm pretty screwed up in the eating department - my therapist wife tells me that if the diagnostic guides in the DSM didn't assume that only ladies get eating disorders, I'd qualify for Bulimia*, which was an exciting factoid! - and I spent a lot of my life believing that big guys like me weren't attractive or deserving of love. I know it wasn't a main point of the story, but I really appreciated the romance as a result!
Moving on, the rest of the story was also sublime. I loved the sadness of the haunted school, and the dawning, creeping impressing that the main character wasn't doing her haunts any favors by keeping them there. The moment where her unreliable nature as a narrator solidified into a certainty that she had been deluding herself was brilliant. The world-building was consistent, the writing was evocative, and the characterizations were solid. It was an excellent story all-around, and I enjoyed it greatly.
By the way, if there are any other big dudes feeling down on themselves, I recommend the Lies of Locke Lamora, which features Jean Motherf^cking Tannen, the baddest bastard of the bunch, and bona fide big guy, who doesn't have to suddenly slim down and turn into a muscle magazine ad in order to get ladies or kick ass!
* Note: Bulimia actually doesn't require throwing up. That's a common misconception. Actually, it's just characterized by a combination of dissatisfaction with your weight, negative body image to the point of mild delusion, and binge eating.