I picked up a 50 1.2L yesteday and am amazed with the DOF. I did some research and don't know if anyone faces the problems i have.
AF: Sometimes it back focuses.. some times it front focuses. I don't know what to expect out of it! I tried micro adjustment but still gives the same issue. It's definitely not due to the focus shift as the subject is more than 5 feet away and i'm shooting wide open.
IQ: It seems the images are a little "foggy". VS my 50 1.8 at f11. The 50 1.2L is softer. At 1.8 vs 1.8 it's a little sharper but still with a little bit what seems to be fog/halo.