I understand that Grant had some impressive victories in the west, before he was called east to take command of all Union armies (and travel with the Army of the Potomac). But Grant's victories at Shiloh came when he was reinforced overnight, and he had superior forces at Vicksburg, whereas we read of Lee's victory at Chancellorsville where he embarrassed a Union force with smaller numbers of men due to his daring tactics and faith in Jackson's abilities.
Was Grant a more skilled general than Lee, or did he prevail based on strength of numbers and materiel? I read accounts of battles at Spotsylvania, the Wilderness and Cold Harbor, and it seems like Grant is unsuccessful tactically, but strikes a strategic blow by inflicting proportionally higher casualties on Lee and redeploying closer to Richmond. I get that a Southern goal was to put political pressure on Washington to force an end to the war and acquiescence to secession (to make the North sick of war), but on the actual battlefield, was Grant a better general than Lee, or was Lee's surrender a forgone conclusion because of differences between North and South?
I'd argue that General Grant had a better understanding of modern industrial warfare (that the American Civil War quickly became) and war of attrition. He knew that the CSA could not replace men and weapon slost at the same rate as the USA could, and any casualties caused to the enemy was good enough.
Grant's primary achievement, I think, was keeping his armies in the field and the pressure on his enemies up - his predecessors in the east had retreated to rebuild their forces after failing to break the Army of Northern Virginia, allowing the CSA forces much needed breathers as well.
Grant kept his army in the field and wore down his enemies - even if he lost battles tactically, he knew he could pay that butcher's bill, while his enemies could not. This was the case during the Vicksburg campaign and this was the case during the Wilderness campaign and the Petersburg campaign. His generalship was steady - he understood logistics, could keep a large army in the field and rotate troops to allow worn formations rest, resupply an reinforcements but was not a tactically amazing general. I'd like to make a comparison - Lee and Grant both needed an aggressive subordinate to force the issue - for Lee that was Jackson. For Grant that was Sherman.
Lee was a good general, but not as brilliant as some want to make him out to be. He never managed to achieve a crushing victory, never managed to conduct a proper battlefield pursuit and struggled to manage the large armies that the American Civil War consisted of. This was a problem for all officers in that war. Lee had the most experience, having done staff work for Scott's 8 000 force that marched on Mexico City.
In general, officers in the American Civil War were severely out of their league in the sizes of forces they had to manage - they learned quickly, but never managed to establish proper battlefield pursuit due to the lack of a strong cavalry establishment.
For example, the Prussians at Königgrätz 1866 took 20 000 Austrians prisoners in battlefield pursuit - in two hours, before the Austrian cavalry counter-charged to protect the retreat of their army.
But Grant's victories at Shiloh came when he was reinforced overnight
That seems post hoc ergo propter hoc to me.
He got into trouble the first day because he hadn't prepared properly, but he and his commanders got the men in hand and won the next day.
he had superior forces at Vicksburg
Because he had had superior numbers at Grand Gulf, Snyder's Bluff, Port Gibson, Raymond, Jackson, Champion Hill, and Big Black River Bridge, because he had maneuvered fast and skillfully, and defeated in detail or dispersed Confederate forces, weakening and pinning Pemberton in Vicksburg. Further, his notion of cutting loose from supply lines before Vicksburg managed to wrest victory from a difficult geographic and strategic situation (they'd tried other advances in more straightforward ways).
Are you asserting that victories with somewhat superior numbers don't count? McClellan and others managed to be defeated with superior numbers, so I think using the tools well should count.