These are not a generational difference, they are different models of mag. The more expensive mags appear to be built for severe duty scenarios, such as counter terrorist teams, repeatedly dropping the gun with the mag hitting the floor, larger temperature extremes, etc
I only have gen1 and 2 mags, the gen2 is durable enough for my needs, and the gen1 have not failed yet (but they do show cracks). My thinking is if I will keep a mag loaded for long periods of time, I should probably get the black mags, If I will load these before I go to the range, cheaper mags mean more bullets per dollar