For me, really the selling point of OpenGL is transparency preview, and another preview that showed transparency would make me just as happy. Speed isn't a big issue to me. I believe DAZ|Studio uses OpenGL for the preview, and I don't know how much of this is OpenGL and how much is 3Delight, but in it, I have to make my scenes insanely dark for the rendered image's light level to be reasonable, so I'm obviously not to happy with that...