You found the zoom at Michael's second hand section?
The zoom is certainly over-priced (2200 US dollars or so) and I found the lens only sharp til f4 or so. The bokeh can be buttery and creamy. The lens is capable of producing good contrasty images.
Autofocus is slow and power zoom does waste your battery quickly. The lens is extremely heavy and I think sigma 70-200mm f2.8 is capable of producing similar quality shots.
I had been dreaming this zoom for so long til I got the zoom. f2.8 produces reasonably ok images in terms of sharpness. The colour seems a bit lacking in this aperture though. f4 is a better aperture to use.
Pentax Fa* 80-200 f2.8 shots