1. The quality of the body materials used; 2. Quality workmanship and fitting parts, the AF switch is stylish and clicks with delicious quality sound, has a white line for greater visibility; 3. Comfortable rubberized zoom and focus rings with a pleasant ride; 4. Weight: weight is reliable.,-); 5. Convenient beautiful hood with an internal corrugated surface and a "correct" lens cap; 6. Complete set: traditionally Sigma puts a semi-rigid pouch with a zipper that can be attached to a belt; I have never practically used these cases, but it is very nice, I already said about the lens hood above; 7. Very quiet and nimble motor; 8. Very accurate and confident AF, if the carcass makes friends with a specific specimen - mine was the only one in the store, but it completely suited me; 9. Sharp on the open, very sharp!; 10. Pleasant blur and pattern, not ugly "correct" nature of distortion, despite the fact that this is a zoom; 11. Sigma USB Dock - inexpensive, and allows you to very accurately rebuild the lens for a specific carcass; 12. Design: exactly the design dictated by logic and common sense, and not what everyone usually understands: it feels like the glass was designed by people who shoot for the same; the zoom mechanism is made in a single housing without any moving trunks, when zooming and focusing, of course, the blocks move inside, which affects the weight distribution and, as a result, if you use a steadicam for video, there is an imbalance, but it is very insignificant. The use of a compedium and/or a battery pack already completely eliminates the imbalance, no reconfiguration is required. Zooms with trunks have to be rebuilt much longer.