My first impression of Grant is that the reason why he won the Civil War was the fact that he was a somewhat lucky general (at least at first) who won the war because he was more willing to sacrifice his own troops for the greater good than his Union predecessors. He seemed to be the first general to realize (and use the fact) that he had greater resources than the Confederacy. I'm not always sure that this was always a good thing, but at least African-Americans had some rights they didn't have before.
When it comes to Reconstruction it seems that Grant was like most Americans (at least when the war started) in his view of African-Americans. He seems to have been able to take them or leave them. He lived in a non-slave state, but if he had, he wouldn't have placed slavery as the primary concern for him. Like most people though, once he'd decided his point of view, he went for it with a gusto.
When it comes to Reconstruction, I would say he was a lot more pro African-American than Johnson, his predecessor, and Hayes, his successor. Johnson comes across as an all-out white-supremacist, and Hayes comes across as someone who would have done whatever he needed to take office. That having been said, I think he was a status quo man. He acted when people did things wrong to the African-American community, but made no effort to lead the country out of the situation.
Finally, I didn't realize that Grant was the President who redefined the Republicans as the "strong money" rather than the "anti-slavery" party, which is something that really interested me, I always assumed that they'd either always been that way or had evolved into the "strong money" party over time.
All in all I enjoyed the book.