I have the 85mm f1.4 and really love it. If you can handle the expense and bulk, you should try one out.
That said, I would also consider a slower 85mm. f1.4 is useful in available-light situations, but depth of field under 10 ft is very shallow. Having eyes sharp and nose blurry isn't often what people want. If you're doing studio-type portraiture where light will always be available, I don't think the extra stop or half-stop is worth it.