This is the most sold lens on FM buy and sell forum. A lot of people buy it but sell it after not using it much. Thats because its a very tricky focal length for composition and if the shutter speed is not atleast 2 x focal length you'll have blurry pictures.
I use this lens mostly in the studio with strobe lights and the images are beautiful - sharp - skin tones clear.
one thing to note - the images from this lens are not much different from my 70-200 F4 non-IS when set at 135mm. So if you are thinking about buying this lens think about saving some $$ and getting the 70-200 F4.