I read this partly because I like Hamilton, and partly because I was curious if I thought it would be OK for middle-grade readers even though it's marketed as teen. (I assumed my 11-year-old daughter would want to read it, but it turns out she's not interested at all, even though she loves Hamilton.) 
 It was a pleasant read, with plenty of historical detail about the war and the setting, but also pretty standard romance writing. It's more accurate than the musical in the setting and sequence of Alex and Eliza's courtship, but adds a whole extra suitor situation that I'm pretty sure is fictional. 
 For middle-graders? I think it's fine. There's a little sexual innuendo during some conversation, plus one assault that isn't described very thoroughly. Any kids who knows the musical has been exposed to similar stuff.