Getting some great responses here. Now I also considered plunking down the cash for the 50L 1.2. A wise choice? Or does the price not justify the purchase over the 50 1.4?What you get for the extra $$ is a lot more glass, better construction, and the ability to have super shallow depth of field.
You have to pay lots of $$$ to get even a tiny improvement. Good used 50mm f/1.4's are available for $250, and are better on FF than the Sigma 50mm. The Sigma is optimized for crop bodies and does very well there.