The 100mm macro has harsh bokeh past macro distance. It should never be chosen as a portrait lens.
I have extensively used the 100mmL IS 2.8 for portrait work and have never experienced harsh bokeh. I have recently loaned it to my daughter who is using it in her capacity as a professional portrait and fashion photographer (Pandora'sThoughts.com), to compare with what she already has and she loves it. It would absolutely be my choice at the price it is.