I've had this lens for two months now and have found it to be excellent in the 70-135 range. Soft at 2.8 and sharp at 4.0 on up. At 200mm it is extremely soft at 2.8, especially at the closest focusing distance. My advice - stop down to at least 4.5. Focus is fast. Tone is slightly warm. Works great with extension tubes and macro diopters.
