My main portrait lens. Everything look great with this, razor sharp at f2, smooth bokeh, fast, built like a tank.
For me the choice between the 135 and 70-200 was the size and weight : I don't want to carry all day long the zoom beast for street portrait photography. And even if it's big, the 135 is a little more "discreet".
A few drawbacks, like purple fringes on high contrasts, AF fast but not always accurate on moving objects (but maybe its the camera). VR could also help a lot, its hard (or impossible) to take low light handheld pictures, unlike the 70-200.
DC was probably great with films, but your can do nearly the same post-processing stuff with digital.
Still I'm in love with this lens.