Comparison of the Sigma 50mm 1.4 and the Canon 50mm 1.2L

I was at National Camera Exchange this weekend and they happened to have a Canon 50mm 1.2 L lens (worth $1600). I was quick to put it on my camera and do a few test shots. Then I put on my Sigma 50mm 1.4 (Worth $400) and took a test shot. I had heard really good things about the Sigma lens before I bought it and after shooting with both that day, I truly believe I chose well. Not sure I will ever buy the expensive L lens with how well my Sigma performed next to it. In fact, I had the darndest time getting a good shot with the L with how slow it was. After taking 10 shots, the one I am sharing was the only sharp one. So, question for ya'all, any chance you can tell which was is the L? All the settings were exactly the same for this comparison.