I tend to favor the use of a longer focal length like this. It gives you more space between your subject and a better, more compact, perspective. The 150 is good for all studio photography purposes, including portraiture and still life. It even does well in the macro/near macro range. Of course its also nice to have a dedicated macro lens for when you get really close. The 150 and 120 macro are my favorite lenses for medium format digital.
For large format digital this gives you a bigger image circle than most "digital" lenses. Its also a good lens for panoramic stitching.
The 105-180mm Apo Sironar Digitals are based off the Apo Sironar S which is regarded to be the sharpest modern large format lens. The shorter focal lengths (except for the 90) are based on the Apo Grandagon a fine wide angle but not quite a Sironar S in terms of sharpness and bokeh. As I understand it the difference from the film versions is that the digital ones were redesigned for larger working apertures, and to be sharper in a smaller image circle. The MTF data shows the digital version to be greatly improved.