I've noticed that Grant normally does fairly badly in the lists of "best presidents", which somehow always end up with the most progressive presidents at the top of the list. When I covered his presidency in school in the mid 90s, it was mostly about the excesses of the Gilded Age and corruption.
I think Grant as president deserves a great deal of credit for his efforts to unify the nation, his alignment with the Radical Republicans and his sincere efforts at Reconstruction, constantly sending federal troops to the South to suffocate violence against blacks and republicans, even after support for Reconstruction was waning in the North. Grant's attorney general, Akerman mercilessly prosecuted the Klan, which largely went extinct until revived in the early 20th century. His Indian policy was well-intentioned, even though in the end the indians ended up losing their lands and freedom. Grant's foreign policy was successful, with no foreign wars and the settling of the CSS Alabama issue with the UK. He also made some attempts at civil service reform.
On the negative side, he had his failed annexation of Santo Domingo, the inflation bill and above all, that his great ability to judge character and ability during his military career didn't translate into his political career, trusting many people of questionable character, tarnishing his presidency and continuing all the way to the end of his life (the Ferdinand Ward ponzi scheme that ruined him and many others shortly before his death). Despite this, his own integrity was never questioned.
From what I read, Grant remained popular and revered in the years that followed his presidency, but his popularity took a nosedive at the end of the century. Was this a result of the "lost cause" mythology that became prevalent at that time?