Overall, neither was the confederate leadership. Take away Jackson and the southern corps commanders in the Army of Northern Virginia were a mediocre lot. The south had, for all practical purposes, a single competent army commander. Division and brigade commanders were about even.
"Overall Union leadership was not stellar." I meant in the East and the first 2.5 years of the war only. The best Union commanders were in the West while the best Confederate commanders were in the East at the beginning of the war. Unfortunately too many promising brigade commanders were killed at the beginning of the war, and who knows how well they would have been if they lived. Even if the Northern commanders were average, the sheer industrial might, efficient rail system and manpower of the North was crushing the South. The ACW was fought at the dawn of the industrial revolution and the people who ran the North were not stupid to take advantage of this economic advantage.
How sad was it that these West Point generals who were classmates and soldiers together ended up trying to defeat each other. It would be like Gen. Myers & Gen. Abizaid trying to kill each other.