I can see why you think I missed @T3hPwnisher’s main point. I agree that the major issues of program selection, proper nutrition, and effective recovery overshadow the particulars like rep speed. However, the sum of my knowledge, based on experience, observation, and research, leads me to disagree with the statement that rep speed is inconsequential.
Occassionally, some of those small details have disproportionately large effects. It appears rep speed, specifically slow, burn-the-muscles-to-pieces negatives are one of those hidden outliers with disproportionate effects.