4/5 stars
This was really great. It kept me up reading later than I intended to most nights. Great job separating the character POV's (Bella's thought parentheses in the middle of paragraphs were great, because I relate to that).
Excellent foreshadowing: enough that you're satisfied when you expected something; not so much that there aren't twists and surprises.
My one complaint is that I didn't know going in that this was alternate history instead of history with fantasy mixed in. Before I figured this out, dates and details bothered me - the fact that the Salem witch trials happened a century later and witches were burned instead of hanged really bothered me until I realized there were other historical figures (mostly authors) who had also been changed. The Brothers Grimm here are the Sisters Grimm; Perrault and Doyle are also women.
I was also never sure where New Salem and Crow County were supposed to be. Descriptions of flora in Crow County, and descriptions of that accent seem to indicate the South, but New Salem is only supposed to be 100 miles from Old Salem which, I assume, is still in Massachusetts.
Still, those are minor complaints from an admittedly very picky reader, and I imagine they won't bother most people.