ive had both the original and the retros and for me, the only difference is the air vent in the original seem to be more functional.. i don't really feelthe air vent working well on the retros..other then that, i don't remember the difference...
but for a quick review on the shoes
cushion : 4.5/5 very responsive - similar to the 2k4
grip : 4/5 very sticky on clean floors, but on dusty floors they drop drastically in grip...
fit: 4/5 - true to size, and the hug your feet very well.
ankle support: 3.5/5 : decent ankle support