Over at
Borepatch's place, a couple of commenters have taken a rather revisionist history that Grant was a better general than Lee:
Robert E. Lee was a great general as long as he had room to maneuver and troops to maneuver with. When he didn't have those things, he was considerably less effective.
Well, now that's interesting. Lee, who was almost always outnumbered and under equipped, wasn't much of a general because he maneuvered his troops. Suggesting that a general shouldn't maneuver troops is like suggesting that a general shouldn't be a general at all.
Great generals have always maneuvered troops. Hannibal consistently out witted the Romans by moving troops around. Rommel, the wily German general of North Africa, kept the British tied up in knots by pitching his forces hither and fore. Of course, Hannibal's victory at Cannae, one of the bloodiest and most deadly in all of history, kept him "maneuvering" around Italy for 8 more years until finally he just left and the Romans won by default. And Rommel often maneuvered his troops so far around the British that they found themselves in desert with no enemy to fight, Germany kinda losing that whole African campaign anyway. So maybe those aren't good comparisons.
But let's look at it this way. Was Grant a good general? Well, if being drunk in battle is a sign of good leadership, sure! From this quarter's issue of
Military History Quarterly:
“I was not long in perceiving that Grant had been drinking heavily,” the newsman later wrote, “and that he was still keeping it up.” Unable to persuade Grant’s aides to intervene, “I then took the general in hand myself, enticed him into his stateroom, locked the room…and commenced throwing bottles of whiskey…into the river.” The reporter eventually convinced Grant to lie down and fanned him to sleep. The general’s drinking continued to be a problem from time to time, but Cadwallader helped manage it, and Grant was grateful. For the remainder of the campaign, the reporter enjoyed all the perks of a member of Grant’s staff.
Eventually Vicksburg did fall. Perhaps things would have turned out differently if General John Pemberton had been shit-faced as well.
Ah! But that wasn't against Lee. So what about Lee vs. Grant.
Well, there's the Battle of Cold Harbor which started when Grant maneuvered his troops around Lee's flank giving Grant a great opening. But things went quickly down hill from that point as Grant attempted to assault Lee in a fortified position. The result was probably the most lopsided of the Civil War, Grant losing 13,000 men to Lee's 2,500.

Maneuvering wasn't part of the picture at the Battle of the Crater either, which occurred just a short while after Cold Harbor. Grant was fortunate enough to have a mining expert in his ranks, and the Union army dug a mine underneath the Confederate lines so that they could set off an explosive charge. And they did, creating a crater that is still visible today in Petersburg, VA. That blast instantly killed 250 Confederates and caused so much confusion that nary a Confederate rifle or canon was fired for a full 15 minutes. Grant took great advantage of the chaos and rushed his troops in... and still they screwed it up. Lee's lines held that day, taking only half the casualties as Grant when the battle was done.
Yes, Lee did end up surrendering to Grant ten months later but not because he was out-generaled. By any length of measure, Lee was the better general.