Rhino SubDs are a bit different. They go to limit surface all the time. So you always see the smooth version of the surface. But, there are ways to extract different mesh levels if the mesh is needed:
SubD - Smooth version
Control Polygon - ExtractControlPolygon Command
Level 1 -3 - Extract Render Mesh and use the SubD slider to control what level mesh to extract.
Of course the Subd can be converted to a NURBS by using the ToNurbs command.
