For me a very nice standard lens I like to use, especially for photos indoors. With Aperture 1.4 you can do with still acceptable ISO actually in pretty dim light still good photos.
In principle, I would quite 5 star awarded when considering the price.
But: Is halt "unfortunately" Sigma and has therefore quite regularly a poorly adjusted autofocus. Was also the case in my lens. Should be adjusted from Sigma as a remedy. If you have a camera with which one can make "Micro Focus Adjustments" is all but not really a problem, so you get the very good itself under control. But actually, something should not be necessary, and therefore there are only four stars.