The only reason I read this is because my grandfather has in his possession a first edition copy from 1880, complete with antiquated blurbs, the signature of the first owner, and a little slip from the publisher correcting a typo.
The book definitely brings the Reconstruction period to life, and Tourgée, a white northerner who came south shortly after the Civil War and would later be the lead lawyer for the plaintiff in Plessy v. Ferguson, expresses a view of the period that's much more widespread than it was at the time he wrote: namely, that the freedmen were simply trying the best they could to exercise the rights of citizens, that they were not in any way to blame for the violence, and that the eventual status quo was quite bad. (As the daughter of a constitutional scholar who specializes in one of the Reconstruction Amendments, I'm the last person to disagree.)
Unfortunately for the construction of the work as a whole, however, the author finds it necessary to continually launch into (for instance) an apologia for the Freedman's Bureau. I sympathize with the desire to be clear about right and wrong, but such blatant abandonment of the plot is only really excusable if one has the pen of Victor Hugo, which Tourgée unfortunately did not possess. The prose is, in my opinion, the main reason why this novel is nearly forgotten, being, aside from the all-too-rare instances of bitter sarcasm, stilted in a very sentimental, 19th-century sort of way.
The characters are all interesting and reasonably nuanced, the Black community being particularly vividly portrayed. There’s a lovely friendship between two freedmen who serve as narrative foils throughout, as well as a romance between a Confederate veteran and a New England schoolteacher which alternates between nicely integrated with the social commentary (such as when he encounters KKK violence and is driven to the realization that Southern white men are the main aggressors) and frustratingly stereotypical (such as when she breaks off communication for a year due to a misunderstanding.
As for the plot, it's occasionally confusing but overall quite effective in showing tragedy mingled with continued hope. Hindsight somehow makes things more and less sad.