So you mean that he effectively used the advantages in numbers and firepower his Armies typically enjoyed? (which were, to a large degree, due to his ability to supply his forces and concentrate them at the right point at the right time).
Sure, but so could alot of other generals of the time. Just not many of the other UNION generals
No, he was apointed to the supreme command of the Army on the basis of his excellent record in the Western Theatre.
Meh, and because Lincoln fired the others before him for incompetence.
Yeah, exactly. There was no way to win campaigns in the Civil War-era without taking heavy casualties. Lee understood this, and his Army also suffered terrible rates of casualties. Anyway, I'd argue that Grant has gotten a bad rap over the number of casualties he took - this seems to stem purely from the Overland Campaign of 1864. He was actually pretty careful to minimise casualties and tried to avoid attacking fixed positions - even the costly Overland Campaign was essentially a manoeuvre campaign. It's also notable that during this campaign Lee's Army, while on the defensive, suffered higher losses in percentage terms.
I'd also argue that a willingness to run risks and learn from mistakes is the mark of a great general, and not a mediocre one as seems to be being argued here. Both Grant and Montgomery accepted risk and adjusted their plans when things went wrong (Monty did himself a great disservice by denying this, when his record as a general shows many instances where he successfully redrew his plans halfway through battles in which his forces were bogged down - eg El Alemain and Normandy).
Well, my argument was against Case saying he was a good general, I found him to just be adequate and good enough to get the job done.