Since I originally went the Nikon route instead of Canon, I bought the 135/2 DC.
I must say, it's invaluable for portrait work on the move, and capturing fast moving grand kids.
I'd highly recommend it for that use.
I tend to use my Fujica 100AE with Auto Up close up lens when I want absolute maximum quality for large enlargements. However, the last time I used that rig, one of my grandsons said, "Grandpa, you're wasting my time"......he was deeply into building a Lego's Star Wars space ship at the time, and I was a little too slow for his needs with tripod placement and manual focus.
So, in my experience, the 135/2 DC has been a fantastic tool for in-hand shooting.
Texsport