um.. one thing.. nurbs are very very flexible to.. and pokeing holes in a nurbs surface takes alot less work than doing it on a poly surface (just use trim)
i usually use polys/subD for organic stuff thats all one piece and nurbs for stuff made out of a bunch of smaller parts
the thing with nurbs is that each model ends up in a lot of small peices

also one thing with nurbs are that the UVs (the way a texture is placed on the surface) are automated..

polys/subDs are kinda like clay and nurbs are more like lego