Not sure if posted but here's Digital Pictures comparison between Canon 50 1.2 vs Sigma 50 1.4 Art
As expected, the Signa blows the Canon out of the water even Sigma at F1.4 vs 50L at f/2.0
Wow. No one would buy (or certainly keep) the 50L if it looked like that. That's a horrible copy. My copy seems a lot sharper than that but without shooting the same target, it's hard to tell.
At any rate, hat's off to Sigma if this is indicative of what people can expect.