For portraits, I can't think of a better lens.
I don't own it because I can't afford it, and because my other c/y lenses suit my needs. I have its little brother, the planar 50 1.4. Closed down to f5.6, it yields one very sharp and 3-D image. I think you will see a more natural reproduction of colors using the Zeiss over your Canon lens, as well.