I tried the 100mm f2.8L IS at Canon showroom recently. Those who mention that it is not suitable for portrait should really go try it out yourself and see. I think this is a value for money L lens, because it can be both a Macro and Portrait lens. In addition, it is not heavy at all, despite it's weather sealed body.
Not forgetting, you can go really close to the subject. If I did not recall wrongly, the MFD is only 30cm, compared to 135L 90cm.
I am sold on this lens already and will be getting it soon. My only consideration now is whether to get it brand new or used......:thumbsup: