I had the Sigma Art for awhile. It was a great little lens, especially for the price, although I did have to calibrate it. It was sharp and focused fast. However, I recently decided to upgrade and I ended up getting the Canon 35 1.4L II, and it is my favorite lens next to my 135L. It completely outperforms the Sigma, especially when it comes to focus. It is sharper, faster, hunts less in lower light, and my keeper rate is much higher than it was with the Sigma. I also haven't needed to calibrate it. It costs substantially more than the Sigma, but IMO, it is worth it if i you're using it all the time. My good friend shoots with the 35 f/2 IS and loves hers, too. That might be another option to consider as well. Tamron makes a 35 1.8 with VC, but I honestly don't have any experience with that lens.