"""""""""""""""You are right Michael. Seeing what is done with Rhino -and so Moi - like http://gallery.mcneel.com/fullsize/46535.jpg
I did not consider models like this helmet as "organic". So in your defintion and philosophy you would recommend to model sth like the helmet with polys ?""""""""""""

For that helmet model, The question would be more "why are you starting that model in a polygon modeler?"

The recommendation would be to start and finish it in MoI!

Sketching, conceptualizing and completing that model in MoI would be much faster than a polygonal modeler for sure...