For one thing, Elisa is not their kind of heroine. Pierce and Cashore write about extremely strong girls, the kind that, even when completely downtrodden, remain strong and determined. This, Elisa is not, although she does eventually gain in strength and confidence. At the end of the book, she is more like one of their heroines, but, in so many ways, she just does not bring them to mind at all.
I liked that Elisa was not the typical heroine at all, at least if I couldn't have my Cashore-esque heroine. Elisa is overweight, lacks confidence and hopes to be able to marry an ugly man. It's nice to read about someone so atypical sometimes. However, as has been pointed out by others, why would you represent her by the waif on the cover. Sure, the cover drew me in, but it now pisses me off. I mean, who is that? For one thing, she probably ways about 90 pounds soaking wet and, for another, she does not look particularly Spanish, as the character names suggest she should. Fortunately, the cover seems to have been changed for the published version. Good call.
The story kept me fairly interested, but I never felt particularly invested. The godstones always seemed weird and I found their ultimate use pretty dang lame. For those who like fantasy stories, unconventional heroines and don't mind some serious religious content, this is worth a try. If you're expecting something like Kristin Cashore would have written, go reread Graceling or fervently prey for the publication of Bitterblue. However, I know that lots of people have loved this, so go check out some of the high praise by authors before dismissing it completely.