Seems like Sigma has 3 good lenses out recently (35 f/1.4, 18-35 f/1.8, and now the 120-300 f/2.8). That is very encouraging. If they get one of their xxx-500 mm lenses to be as good, I'll definitely be taking a long hard look. The 120-300 f/2.8 seems like a great lens. But for the money and weight, I'll go with the 70-200 f/2.8II plus the 1.4x extender and lose a stop. These seems like it is really for those that want a less expensive way to get to f/2.8 at 300 mm.