I used Sigma's "pro" EX series of lenses for quite a few years and was very happy with them. Of course that was back when sensor resolution was a lot lower so they may not hold up as well these days with the likes of 20+ mp sensors.
So after tossing up buying either the new 50mm f1.4 art or the 35mm version I finally opted for the 35mm. Because I was finding I more often than not wished for a little wider field of view when shooting with my Canon 50mm f1.2L on shoots with families and in tight spaces at weddings etc..
I managed to pick up the lens at a bargain price from here in Japan. But you can get it at the US Amazon store by clicking here.
Here's a little unboxing and initial thoughts on the new lens in my video here.
Here are a few test shots I made with the Sigma 35mm f1.4 art on a Canon 5DmkIII lens around home and just down the street at sunset with my MR2 Spyder.
All samples were shot at f1.4