I shoot with 50L about 75% of the time and love it. It isn't the sharpest lens I own but the images are awesome and it feels awesome.
I wouldn't say it is a soft focus, as I have had some very sharp shots from it.

AFMA is a must with this lens. But even that has to be dialed in to shooting style. I never use the center or inner AF points so I adjusted the AFMA to an outer point. I attribute this to my successes with this lens where others have been frustrated with it's inconsistencies.

The place where I've noticed it's weakness is at further distances; for example, shooting full length shots. Even shooting at f/8 or higher the images don't look soft focused, they just look like the lens couldn't resolve enough detail. The outer portions and just too soft to keep faces tight on full length shots. The 85LII at further distance for same framing will BLOW the 50L out of the water.

The 50L is NOT going to be as sharp as the 35L. I find the 50mm focal length more useable though.