I agree about Lee, but you are far too dismissive of Grant. He wrapped up the war in the west which allowed him to turn his attention to Lee. He didn't do anything spectacular against Lee, but he ground the Army of Northern Virginia down. His one mistake against Lee was the suicidal attack at Cold Harbor. Once he saw that he could not carry the southern position in an attack, he simply let time take its course and whittled away at them.
Grant's gracious behavior toward Lee and his men at Appomattox helped the war end with less bloodshed than it might have. Grant was the general the Union needed. Had he been in command earlier in the war, Lee might not have enjoyed that great year of success. Grant would not have been cowed like McClellan, Burnside, Pope and Hooker.
Cold Harbor was a harbinger of WWI’s trench warfare.
And unlike Lee, Grant learned from his error. His slipped away from supposed genius Lee and crossed the James river in one of the most brilliant feat in the Civil War.
Grants biggest problem in the East was being hobbled with divisional and brigade commanders who were completely defensive minded out of fear of Lee. Petersburg VA should of taken long before Lee ever got his troops moving if Grant's tactical commander on the scene Quincy A. Gillmore' had had even a modicum of skill.
Modern research have discovered that the casualty count at Cold Harbor may have been badly overstated. Gordon Rhea has written a five volume history of Grant's Overland Campaign and his research leads him to reach a casualty count of between one-quarter and one-third of the popularly quoted 12,000 killed, wounded, and missing.