If your top priority is bokeh, look no further. This lens is a bit big, a bit heavy but absolutely awesome. It opens all the way up to f/1.2 for extreme low light situations with an end result of amazingly smooth out of focus areas. However, with great power comes great responsibility as the 85L falls into the high-risk/high-reward camp. If you're going to try to shoot wide open, be sure to really check your focus critically. Nothing is worse than thinking you've got the shot only to get home and realize you missed focus.
The real treat of this lens is shooting at apertures like f/2.8-f/4 and getting simply stunning results. At those apertures, you really get into the sweet spot of its performance. If there was one big knock for this lens its that the AF can be a bit slow with all that pretty glass to move around. If you're shooting video, one other thing to consider is that the elements in this lens are so big that there was no room for a traditional mechanical manual focus. This lens is "focus-by-wire" meaning that when you rotate the manual focus ring, all you're doing is driving the AF motors so rapid snap rack focusing isn't this lens's strong suit.
Overall we love stopping this guy down to f/2.0 then going for some razor-sharp subjects with dreamy backgrounds. Plus if you pop it on to a 1.6x crop-factor camera and it becomes a 135mm focal length, fantastic for portraits whether you rock a full-frame or a cropped sensor.