I don't think you'll find many differences in velocity or pressure in new factory loaded brass. It's far better for corrosion resistance etc. HOWEVER, I don't think you'll find many reloaders using nickel plated brass because you'll likely need carbide dies, it flakes after a few loadings, is more brittle, and is usually more expensive. BUT, if you want to buy factory loaded ammo or only load it once or twice to put away for hunting ammo, it's good stuff. At least that's my experience.