Not only does the camera body make a difference, but personal taste for blur should be taken into account.
For example, Vern's lovely wedding shot above has too much blur for my taste. I'd rather have a little less blur and be able to identify my friends/relatives in their wedding pix. I think photographers may have gotten a bit carried away in seeking maximum blur. Do clients really want that? I think they are more concerned that we don't make them look fat. BTW, I'm not a wedding photographer, so my opinion should not be given a lot of weight. - pun intended
Personally, on my 5D3, I prefer the 85 1.8 for its light weight and speedy autofocus. In my recent side by side test, the images were quite similar. But of course the 85 1.2 can create more blur if you shoot at 1.2.
All I need to do now is find a way to paint a red ring on my 1.8!
Thanks - I did also manage to focus a few shots on the subjects. ;)The 1.8 is a very nice option and certainly much lighter than the 1.2 - although at 1.8, the IQ of the 1.2 is much better. Not sure if the bokeh at the same aperture would be equivalent either. I do shoot at 1.2, but the DOF is so shallow that getting more than one subject in the focal plane is a challenge.