Bogging in again, I prefer the 70-200 2.8II IS (for flexibility) and the 85 (I have the Sigma) for portraiture personally. The 100L is great for macro but I just don't have a meaningful place for it in my own kit. If I didn't have the 70-200 2.8 then I would possibly find it more useful (the IS, for one) but when the option for truly luscious DOF lurks just around the corner at 85, I find it hard to justify the comparatively slow 100L at 2.8 (even if the bokeh is sweet).