My weekend with the 50L has been very interesting. I've shot many different scenarios both indoors and outside and at many different apertures. The lens has been paired with my 7d which is my main camera body. BTW, I'm very familiar with my 7d and it's AF system. I don't get OOF shots unless I've had a brain fart. Just this afternoon, I was taking a few shots of one of our cats with fill flash at f/1.2 and f/1.8. When I was comparing the two shots in LR, I was surprised that the f/1.2 was sharper. I understand that the 50L can be softer at f/1.2, but based on my testing, technique may have something to do with it.
I must confess that the images of this lens are very different than the other L primes I use. It's hard to describe, but the images seem "dreamier" and not as much edge blur as the 85L II. I use my lenses as tools to achieve a "look" in the images I photograph and the 50L has a very unique look about it unlike my other primes. I've decided to buy the lens and I anticipate that it will find itself attached to my 7d a lot.
Congratulations! Glad you're enjoying it. And yes, it does very well on an APS-C sensor, it's like having an 80mm 1.2 with the minimum focusing distance of a 50L