The 180 makes a superlative long portrait lens.
Note that it is on the long side for a portrait lens, best suited for head shots (with similar framing to a passport photo). Once I clear myself out of a pile of other priorities, I expect to do a fair amount of work with it doing exactly that type of shot for starving musicians and actors.
Motion blur will depend on shutter speed, of course. But 1/250 @ f/8 gives you everywhere from ISO 50 in midday snow to ISO 800 at sunset, so you shouldn't have any problems there. It's perfect in the studio, where flash will take care of any movement.
The only thing you're not going to do with the lens is create razor-thin depth of field shots, though you can still get fairly thin with unidentifiable backgrounds. But f/8 is just about perfect with this lens...the whole face is in focus, and the hair at the back of the head is just a bit soft.
I'm attaching a few portraits I've taken with this lens. Eric, the clarinetist, still raves about this shot, saying it's the only picture of himself he's seen that he likes.