Both lenses support image stabilization -- not enough wide-ish-angle lenses do for systems from Canon and Nikon that don't have in-body stabilization. As with Sigma's recent designs, the switches are very big and easy to feel without looking.
Note that the sample photos are ones that I quickly shot in our offices. I couldn't take the lenses outside until they were announced. Check back for a wider range of samples post-launch. They were all shot with the Nikon D810.
You can see a little fringing on the high-contrast edges.