Here are some comparison pics for the Black/Red XIXs...The most notable differences I noticed are:
The suede on the OGs is much better
The patent leather is also better on the OGs
The retros are a little brighter shade of red both on the inside of the shoe and the sole (it's kind of hard to see it in my pics)
The toe box on the retros is a bit more narrow that the OGs...OGs much more comfortable in that aspect...
As far as the Zoom Air cushioning...both are the same (to me anyways)
I think that's it...on to the pics...Hope they help. The retros are on the left and the OGs on the right in all the pics.

Click to show pictures

Click to show pictures

Click to show pictures

Click to show pictures

Click to show pictures

Click to show pictures

Click to show pictures

Click to show pictures
I love my ogs more for this. The techflex looks smaller and not even the same shape