Well, Josh - these two are very different lenses to me. Love both of them, but for maximum isolation I always choose 135L as well as when I'm shooting overactive toddlers/kids because of the much faster AF. Also color wise 85L gives me more dreamy tones whereas 135L is more contrasty and deeper/richer colors. Of course I always play with the colors in post processing, so you cannot go wrong with either. Also I used lots of 200/2.8L when my 135L was stolen and found that I quite like it for the same type of shots. Maybe it's better to give you some examples:
You have some amazing work on your flickr.