I’m going to ramble here. Sorry. If you have to ask this question, you need to see both in person. I have a Crafted By Inifinity superideal and researched meticulously here on PS before I bought it. I also own some antique diamonds.
The light return, fire, and light play of my superideal CBI is endlessly interesting and beautiful to me. However the facets are small, which I don’t prefer, I prefer chunky flash. The other strong point of my superideal is that I was able to buy an E color diamond (it’s an SI1 and small). It is extremely rare to find a colorless old cut. I appreciate color more than anything else besides cut. So, benefits of superideal are you can control color and cut. Cut will be exceptional. With an OEC in particular you can likely find a well cut one but the color will likely be K or lower in larger stones. That’s all. If you want the larger flashes of light, with historical value of antique artistry and a past, with a warmer color, go for the OEC. If you want a splintery, firey disco ball that is backed up by a nice trade in policy, go superideal.