Open Pro rims are made from a higher-performing alloy called Maxtal. So strength-to-weight ratio is better.

Open Sport rims don't use this alloy, and I don't know if they have two-story "double" eyelets to distribute spoke tension stress between the inner and outer walls of the rim.

I think of both of these rims as old-fashioned though, since riders today are preferring wider rim profiles for what I think are very good reasons.

I've built a few rear wheels for my CX bike using Open Pro rims over the last 20 years, and it's a pretty good rim imo. I did adjust my build to use thicker spokes after bending a couple of rims with very thin spokes.
The events that caused bending were slides where the tire catches traction after sliding out (700c rims can be fragile in this regard).