The Sigma 30mm f/2.8 DN Art features a strong contrast profile that is fairly rare among cheaper lenses. There is some bite to the images. Some of this is attributable to the high image sharpness, but the overall contrast of the images is quite high as well. This contrast actually is reminiscent of the typical Zeiss drawing style, though the Sigma differs a bit from Zeiss in how colors are rendered.
While the contrast profile reminds me of Zeiss lenses, the Sigma does render colors a bit more on the warm side, which I generally like. The color output is warm but evenly saturated. RAW files will need a bit of a saturation boost, but the color response is very good when pushed in that regard.