The Sigma APO 120-300mm f/2.8 EX DG OS HSM will allow Sigma to offer second generation image stabilization (with the ability to reach 4 EV improvements) on a wide aperture tele-zoom lens (f/2.8). Now, this is usually the realm of the very best lenses (the f/2.8 aperture at 300mm is normally associated in our mind with exceptional quality prime lenses – See Canon, Nikon or Sony).
One SLD and two FLD glass elements, to reduce chromatic aberrations. The Super Multi-Layer Coating treatment to reduce unwanted reflexions and lens flare. 9 rounded blade diaphragm. AF driven by an HSM motor. Sigma did not leave any available technology out. They seem to be intent on making an excellent lens.
The result will have to be checked and compared with the undisclosed 3200€ price. Sigma is capable of the best or the less than best depending on the balance chosen by the Marketing Department. But it seems already going in the right direction.